Query about Question 19 from "Arithmetic Foundation Quiz #1" [1726]

GRE GRE Quant Problem Solving
1

Link: https://www.gregmat.com/quizzes/quiz/arithmetic-foundation-quiz-1-yhnf (Question 19)

How’s option (c) incorrect here?

2

Quantity A:
-21/15+1/8+0.4 = -21/15+1/8+2/5

Quantity B:
2/5 + 0.125 - 7/5 = 2/5 + 1/8 - 21/15= -21/15+1/8+2/5

These quantities are the same. I submitted C, and it marked it as correct.