The answer would be B<C<A
Recipe A would have used 0.25 of a banana per muffin.
You get this answer by divide the number of bananas by the number of muffins.
3 ÷ 12 = 0.25.
Recipe B would have used 0.208 of a banana per muffin.
5 ÷ 24 = 0.20833333 ( a lot of threes ) so you round down ( because 3 is less than 5 ) which gives you approximately 0.208.
Recipe C would have used 0.2292 of a banana per muffin.
11 ÷ 48 = 0.22916666 ( a lot of sixes ) so you round up ( because 6 is more than 5 ) which gives you approximately 0.2292.