What are some potential issues with using focus groups as a research tool?

pick the choice below that best answers this question

a) Focus groups can never yield valid data because participants will always be trying to tell the researcher what he/she wants to hear

b) One person's opinion may sway the rest of the group's decision

c) Consumers may be more attentive in focus group than when they are in the store AND one person's opinion can sway the rest of the group

d) Not being able to record them clearly because there are too many participants

E) Consumers may be more attentive in a focus group than they naturally would be when in a store