What’s the reason for twins to be at a disadvantage in their intellectual development?

• A、They can only understand their own private language

• B、They communicate with outsiders less than non-twins.

• C、There is little stimulation for them.

• D、Adults don’t like to talk with them.

The author probably feels that twins’ problem 

• A、can not be solved because solution is very cruel

• B、can be solved because twins will be separated

• C、can not be solved unless the twins are forced to live in an ordinary environment

• D、can be solved if the adults communicate with them more often

59（）