For the formula, 1 + 4 + 7 +........ + (3n - 2) = n(3n-1)/2 where n > 1, when n = (k + 1), the formula is: A. B. C. D. 1 + 4 + 7 +........ + (3k - 2) + (3(k+1) -2) = n(3n-1)/2 1 + 4 + 7 +........ + (3k - 2) + (3(k+1) -2) = (k+1)(3(k+1)-1)/2 1+ 4 + 7 + + (3(k-1) -2) + (3-2) + (3(k+1) -2) = n(3n-1)/2 1 + 4 + 7 +........ + (3(k-1)-2) + (3(k+1) -2) = (k+1)(3(k+1)-1)/2 Select one: O a. D ob. A . O d. C