FERMAT 2023 Problem 11

At the start of this month, Mathilde and Salah each had 100 coins. For Mathilde, this was 25 \% more coins than she had at the start of last month. For Salah, this was 20 \% fewer coins than he had at the start of last month. The total number of coins that they had at the start of last month was

Answer Choices
A. 180
B. 185
C. 190
D. 200
E. 205