Answer:
D. Focus groups allow for multiple viewpoints to be heard.
Explanation:
A focus group is a form of recollecting data and information through various viewpoints within a group. It is commonly used in marketing or psychology even, in order to receive feedback from clients/ subjects for research.
Focus groups allow multiple viewpoints to be heard in order to optimize the product or get more information about a study, for example.
The other options are disadvantages;