This is simple, no worries!
See, what we do here is the percentage thing.
We know the total, and the number of people who prefer digital or hard copies.
Digital = 4
Hard = 21
Total = 25

× 100 = 84%

× 100 = 16%
Therefore, the most likely statement that is true is:
A. About 84% of the grandparents prefer the hard copy