“于生效之日起，此协议有效期为三年。”的英文是（ ）
A.This agreement shall become effective as of the effective date and shall remain in effect for three years. B.This agreement will become effective as of the effective date and will remain in effect for three years. C.This agreement will come into effect as of the effective date and will remain in effect for three years. D.This agreement shall become effective as of the effective date and will remain in effect for three years.正确答案A
