Question writers have to find different ways of asking the same question. Here we're being asked the Greatest Common Factor of 20, 28, and 44. Let's calculate that; then we'll talk about why.
Answer: 4
Because 4 is a factor of 20, 28 and 44 it makes a rectangle with each of them: 4 by 5, 4 by 7, 4 by 11. Because 4 is the greatest common factor, that's the greatest number of rows that can be a common factor, which is what the question asks.