Biology

The correct answer is: A.double membrane, an inner and an outer, which surround a third inner-most membrane.

Explanation:

1.Chloroplasts have a double membrane structure: an outer membrane and an inner membrane. Inside the inner membrane, there is a third membrane system called the thylakoid membrane. The thylakoid membranes are organized into stacks called grana, and these are where the light-dependent reactions of photosynthesis occur.