General Principle

Correct Example

C11 a) When parentheses are inside a sentence, end with a period. 

This sentence has parentheses in it, so it will end with a period (or other end-punctuation). 

C11 b) When sentences are inside parentheses, end with parenthesis. 

(However, there can be one or more whole sentences inside parentheses.  In these cases, they end with a parenthesis.)