If a Child with a Physical Disability Joins a Class

If a child with a physical disability joins a class and the other children want to know why the new student cannot do the same things as everyone else, what should the teacher do?

A) Tell them to pretend they do not notice the differences.
B) Clearly and honestly explain the child's condition and abilities.
C) Make up a simple explanation to avoid upsetting the children.
D) Explain that it is none of their business and is not to be discussed.