Which one of the following contract is void?

A. A' and 'B' contract to marry each other, Before the time fixed for the marriage, 'A' goes mad

B. 'A' and 'B' contract to marry each other at the early date, 'A' insists on marriage immediately after expiry of one month from the date of the contract

C. 'A' and 'B' contract to marry each other, but 'A' can fix the date of marriage only after his return from England where he had gone for business

D. 'A' and 'B' contract to marry each other, Before the time fixed for the marriage, 'A' fails fill and his physician advises 'A' to take rest in bed for one month

Answer: Option A