To solve problem A follow the steps below...
Step 1: When changing a mixed fraction into an improper fraction you multiply the denominator by the whole number and add the numerator to that product and use the same denominator as before
2 1/4=4x2+1=9/4
1 1/4=4x1+1=5/4
2 3/4 =4x2+3=11/4
For problem B I would suggest doing research on fraction diagrams/manipulative because I am not really sure how to explain that problem. I'm sorry
To solve problem C follow the steps below...
Step 1: Compare the mixed fractions you had from problem A and see which fraction is the largest
9/4-Crab
5/4-Lobster
11/4-Shrimp
Answer: Shrimp because 11/4 is larger than 9/4 and 5/4
I hope this helps and I apologize in advance if I gave any false information. I'm sorry I couldn't answer all of your questions.