Food Web:
A food web is a complex network of interconnected food chains that shows the feeding relationships between various organisms in an ecosystem. It represents the flow of energy and nutrients from one organism to another within the ecosystem.

Explanation:
When an organism of a higher trophic level feeds on several types of organisms belonging to a number of lower trophic levels of different food chains, it forms a complex feeding relationship known as a food web.

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

1. Trophic Levels:
- Trophic levels are the positions that organisms occupy in a food chain based on their feeding habits.
- Producers, such as plants, occupy the first trophic level as they convert sunlight into food through photosynthesis.
- Primary consumers, such as herbivores, occupy the second trophic level as they feed on producers.
- Secondary consumers, such as carnivores, occupy the third trophic level as they feed on primary consumers.
- Tertiary consumers, such as top predators, occupy the fourth trophic level as they feed on secondary consumers.

2. Organisms of Higher Trophic Level:
- Organisms of a higher trophic level are those that occupy a trophic level above the primary consumers.
- They primarily feed on the organisms from lower trophic levels to obtain energy and nutrients for their survival.
- These organisms are often carnivores or omnivores that can consume multiple types of organisms from different food chains.

3. Feeding on Several Types of Organisms:
- The organisms of higher trophic levels in a food web feed on several types of organisms from different trophic levels.
- For example, a top predator can consume herbivores from one food chain, as well as carnivores from another food chain.
- This feeding behavior allows them to obtain a diverse range of energy sources and nutrients.

4. Interconnected Food Chains:
- A food web consists of multiple interconnected food chains that represent the feeding relationships within an ecosystem.
- Each food chain in the food web represents the transfer of energy and nutrients from one organism to another.
- The organisms of higher trophic levels in the food web play a crucial role in maintaining the balance of energy flow within the ecosystem.

Therefore, the organisms of a higher trophic level that feed on several types of organisms belonging to a number of lower trophic levels of different food chains constitute a food web.