The arithmetic sequence is 40, 47, 54 etc. In this case, the arithmetic difference is 7 and a1 being the first term is 40. Hence the arithmetic equation is an = 40 + 7*(n-1) where an is the nth term and n is an integer. Hence the answer to this problem is B.a_n = 40 + 7(n − 1) where n ≥ 1