Frank studied for two M.A. degrees, and he earned a doctorate before he landed his current post, as a math instructor. Choose the selection in which the sentence is properly punctuated. A) NO CHANGE B) Frank studied for two M.A. degrees, and he earned a doctorate before he landed his current post as a math instructor. C) Frank studied for two M.A. degrees and he earned a doctorate before, he landed his current post, as a math instructor. D) Frank studied for two M.A. degrees, and he earned a doctorate before he landed his current post; as a math instructor.