Assertion (A) : Endosperm is completely consumed during the development of embryo in ex-albuminous seeds. Reason (R) : Castor, pea and beans are all examples of ex-albuminous seeds.

The correct option is: Assertion (A) is true, but Reason (R) is false.

Step-by-step Explanation:

1. Evaluation of Assertion (A):
Based on the presence or absence of endosperm in mature seeds, they are classified into two main categories:
• Ex-albuminous (Non-endospermic) seeds: In these seeds, the endosperm is completely consumed by the developing embryo during development, and food is typically stored in the cotyledons. Examples include pea, gram, groundnut, and beans.
• Albuminous (Endospermic) seeds: In these seeds, the endosperm is not completely consumed during embryo development and remains in the mature seed to nourish the germinating seedling. Examples include castor, maize, wheat, and barley.
Therefore, the statement that endosperm is completely consumed during the development of the embryo in ex-albuminous seeds is correct. Thus, Assertion (A) is true.

2. Evaluation of Reason (R):
Reason (R) states that castor, pea, and beans are all examples of ex-albuminous seeds.
While pea and beans are indeed ex-albuminous seeds, castor is an albuminous (endospermic) seed because it retains a prominent, food-storing endosperm at maturity.
Because castor is not an ex-albuminous seed, the statement in Reason (R) is false.

Conclusion:
Assertion (A) is true, but Reason (R) is false.