Seven caterpillars were lined up in a row. Each caterpillar was 1 2/15 inches in length. How long was the row of caterpillars? Manuel solved the problem below. What was his error?

7(1 2/15)
7(1+2/15)
7 + 2/15
7 2/15

a) The fraction was not simplified in the last step.
b) 7 was not multiplied by 2/15.
c) There should be a subtraction step, not an addition step.
d) 1 should have been multiplied by 2/15.