An example of a fruit that develops from a single carpel is

Analyze the question: We need a fruit that develops from a single carpel, meaning a flower with one carpel (a monocarpous gynoecium).

Concept:

• A carpel is the female unit of a flower (stigma, style, ovary).
• If a flower has one carpel, the fruit is simple and develops from that one carpel. Legumes are the classic example.
• If a flower has several fused carpels (syncarpous), the fruit develops from a multi-carpellate ovary.

Checking each option:

• A. Okro: The ovary has five fused carpels, so it forms a capsule from multiple carpels. ✗
• B. Tomato: A berry from two or more fused carpels (bi- or multilocular). ✗
• C. Bean: The flower has one carpel, and the fruit is a legume (pod) that splits along two seams. ✓
• D. Orange: A hesperidium formed from many fused carpels (the segments). ✗

Answer: The bean (a legume) develops from a single carpel, so the answer is C.

Exam tip: Remember "Legumes = Lone carpel". Beans, peas, groundnut and cowpea all belong to the family Leguminosae and have a single carpel. Fruits like okro, tomato and orange are made from fused carpels.