The correct answer is option 'D', which states that the percentage of carbon in bituminous coal is in the range of 65 - 80%.

Bituminous coal is a type of coal that is commonly used for electricity generation and industrial processes. It falls in the middle of the coal rank classification, between sub-bituminous coal and anthracite coal. Bituminous coal is known for its relatively high carbon content, which makes it a valuable source of energy.

Here is a detailed explanation of why option 'D' is the correct answer:

1. Definition of bituminous coal:
- Bituminous coal is a black or brownish-black sedimentary rock that is primarily composed of carbon along with various other elements such as hydrogen, sulfur, oxygen, and nitrogen.
- It is formed from the remains of plants that lived and died millions of years ago, and underwent geological processes such as burial and heat exposure.

2. Carbon content in bituminous coal:
- The carbon content in bituminous coal is relatively high compared to other types of coal.
- On average, bituminous coal contains about 60-80% carbon by weight.
- This high carbon content is responsible for the high energy content and heat-generating capabilities of bituminous coal.

3. Range of carbon percentage in bituminous coal:
- The given options state that the percentage of carbon in bituminous coal is of the order of 65-80%.
- This range is accurate and represents the typical carbon content found in bituminous coal.
- The lower end of the range (65%) includes bituminous coals with a slightly lower carbon content, while the upper end (80%) represents bituminous coals with a higher carbon content.
- The exact carbon percentage can vary depending on the specific coal deposit and its geological history.

In conclusion, the correct answer is option 'D' (65-80%), which accurately represents the range of carbon content in bituminous coal.