The correct answer A) is future progressive.
The verb tense and aspect of “Susan will be working as a camp counselor this summer” is future progressive.
When we are talking about the future progressibe tense, it means there is a continuing action that is going to be developed by someone or something in the future. The tense uses the modal WILL and then, BE and the verb in gerund form. For instance, I will be playing football next Sunday. Or, you will be eating luch after class.