Sheryl Is Having a Hard Time Learning the Material in One

Sheryl is having a hard time learning the material in one of her courses this semester. She's been studying in the library when she can find the time. On a day when she was unable to find a place to sit in the library, it was suggested to her to reserve a study room ahead of time. She said she would try, but that she is usually too busy to schedule study sessions ahead of time. This is an issue with:

A) Use of time
B) Regulation of physical environment
C) Regulation of social environment
D) Monitoring performance
E) Methods of learning