Correct Option: B

Lets assume the number as N.
Since when this number is divided by 899 it gives us the remainder 63 implies.
N - 63 is divisible by 899.
So the question is what would be the remainder when this number is divided by 29.
Since 899 is multiple of 29.
Implies all the numbers that are divisible by 899 are also divisible by 29.
So N - 63 is also divisible by 29.
But we need what is the remainder when N is divided by 29.
So the answer would be the remainder when 63 is divided by 29.
So the remainder is 5.
Explanation :
Since N - 63 is divided by 29
Then N - 63 + 29 must be divisible by 29
=> N - 34 is divisible by 29
And then N - 34 + 29 is also divisible by 29
=> N - 5 is divisible by 29
So the remainder will be 5 when N is divided by 29.