Chlorophyll are light harvesting cyclic tetrapyrrole compounds. The chlorophyll biosynthesis requires iron and magnesium mineral ions. The succinyl CoA, an intermediate of Krebs cycle and the amino acid glycine initiate the biosynthesis of chlorophyll 'A', leading to production of protochlorophyllide or protochlorophyll. The protochlorophyllide or protochlorophyll is converted to chlorophyll 'A' in presence of light. Thus, In angiosperms chlorophyll synthesis is a reduction process occurring in the presence light.

Synthesis of chlorophyll in angiosperms occurs in the presence of light.

Light is an essential factor for the synthesis of chlorophyll, which is the pigment responsible for capturing light energy during photosynthesis. The process of chlorophyll synthesis involves several steps and requires specific conditions, including the presence of light.

Here is a detailed explanation of why the correct answer is option 'B' (Light):

1. Importance of chlorophyll:
- Chlorophyll is a green pigment found in the chloroplasts of plant cells.
- It plays a crucial role in photosynthesis, the process by which plants convert light energy into chemical energy.
- Chlorophyll absorbs light in the blue and red regions of the electromagnetic spectrum and reflects green light, giving plants their characteristic green color.

2. Chlorophyll synthesis:
- The synthesis of chlorophyll occurs in the chloroplasts of plant cells.
- It involves a series of enzymatic reactions that convert precursor molecules into chlorophyll molecules.
- The key precursor molecule in chlorophyll synthesis is a compound called protoporphyrin IX.
- Protoporphyrin IX undergoes several chemical modifications, including the insertion of a magnesium ion, to form chlorophyll.

3. Light-dependent reactions:
- Light is a crucial factor for the synthesis of chlorophyll because it is required for the activation of certain enzymes involved in the process.
- During the light-dependent reactions of photosynthesis, light energy is absorbed by chlorophyll molecules in the chloroplasts.
- This absorbed energy is used to generate ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate), which are energy-rich molecules that drive the synthesis of glucose and other organic compounds.
- The ATP and NADPH produced during the light-dependent reactions are also required for the synthesis of chlorophyll.

4. Role of phytochrome and cytochrome:
- Phytochrome and cytochrome are two different types of pigments found in plants, but they are not directly involved in the synthesis of chlorophyll.
- Phytochrome is a pigment that plays a role in regulating various plant processes, including seed germination and flowering, in response to light.
- Cytochrome is a pigment involved in electron transfer reactions during cellular respiration.
- While both phytochrome and cytochrome are important for plant growth and development, they do not directly participate in the synthesis of chlorophyll.

In conclusion, the correct answer is option 'B' (Light) because chlorophyll synthesis in angiosperms requires the presence of light. Light provides the energy necessary for the activation of enzymes involved in the synthesis process, as well as for the generation of ATP and NADPH, which are essential for chlorophyll production.