please answer this. very important! :))

Total length = 14h + 14b + 42
Total length (h) = 2h . 7
Total length (h) = 14h
Total length (b) = 2(b + (b + 1) + (b + 2) + ... + (b + 6))
Total length (b) = 2(7b + (1 + 2 + ... + 6))
Total length (b) = 2(7b + 21)
Total length (b) = 14b + 42
Total length = total length (h) + total length (b)
Total length = 14h + 14b + 42
Total length = 14h + 14b + 42