Answer:
A) blanc
Step-by-step explanation:
The form of the word used is singular, we can tell from the use of the word le instead of les, which is the plural form. This means we can rule out options B and C, which are plural because of their use of 's' at the end.
Also, the word le is masculine. The feminine form of the word, la, is not used. So, we need to use a masculine form of the adjective as well. Blanche is feminine, so the answer cannot be D either.
Option A is blanc, which is singular and masculine. The answer is A.