I'm going to convert all the values given to you in percentages, so hopefully you should be able to see the correct answer a little clearer. :)
Debbie said that 21/50 drink coffee in the morning. 21/50 can also be written as 42/100, and now that it's out of 100, it's basically a percentage. (42%).
Allen said that 45% of people drink coffee in the morning. His value is already written as a percentage, so we won't do anything with it.
Benny says that 0.495 of the people he surveyed drink coffee in the morning. 0.495 is the same as 49.5% (multiply it by 100 to get it in a percentage).
So, in Debbie's survey, 42% of people drink coffee. In Allen's survey, 45% of people drink coffee. In Benny's survey, 49.5% of people drink coffee.
