A,
B, C and D collected one-rupee coins following the given pattern.

Together
they collected 100 coins.

Each
one of them collected even number of coins.

Each
one of them collected at least 10 coins.

No
two of them collected the same number of coins.

If
A collected 54 coins, then the difference in the number of coins between the
one who collected maximum number of coins and the one who collected the second
highest number of coins must be at least

If
A collected 54 coins, remaining will be 46.

Now
B,C,D must have atleast
10,12,14 coins

So
remaining coins will be 10

So
difference between maximum and second maximum should be least when second