Answer:
B. 3
Step-by-step explanation:
In order for the sentence to have five people in the committee, "I think Robert Mary Jane Andrea Lee Ann and Milton should be on the planning committee" will have to be made into "I think Robert, Mary Jane, Andrea Lee, Ann and Milton should be on the planning committee" or anyway by adding three commas within the names. The positioning of the commas can be anywhere within the names but only as far as correct names can be obtained.