The Boo baby has learned to roll . He rolled from tummy to back the first time when he was about a week old and has done it a few times since . About three weeks ago he figured out how to roll from back to tummy over his left side , and he 's been a rolly - poly boy ever since . Now , when we lay him in the floor , he will roll back to tummy to back to tummy over and over again .
According to the above context, choose the best option to answer the following question.
Question: Why did the baby roll back and forth ?
Options:
A. None of the above choices .
B. He was learning to walk .
C. He was learning to sit up .
D. His clothing was uncomfortable .


C