Question 4: A. Since the plan's approval B. Once the plan's approval C. While the plan is approving D. When the plan is approvedĐoạn văn4/40Mark the letter A, B, C or D to indicate the correct option that best fits each of the numbered blanks from 1 to 6.Since the plan's approvalOnce the plan's approvalWhile the plan is approvingWhen the plan is approvedGiải thíchChọn đáp án A