There are 50p, 25p, and 10p coins in the ratio 4:7:3, amounting to Rs. 202.5. Find the number of coins of each type, respectively.
a) 200 coins, 350 coins, 150 coins
b) 150 coins, 300 coins, 200 coins
c) 100 coins, 400 coins, 100 coins
d) None of these