" Never having seen him my mother could not know the portrait was heavily retouched"
Explanation:
We can infer that the quotation that provides the best evidence for the central idea is " Never having seen him my mother could not know the portrait was heavily retouched"
The attached document below further explains the answers because at the point of submitting this answer , there is a system glitch that makes me unable to submit the answer; so i created a word document instead and attach it below.
