Answer:
1. d. comma/but
The first compact microwave ovens were sold in 1960, but not everybody used them until the 1980's.
2. d. comma/but
For centuries people ate with their hands, but change finally occurred in the 1100's when people used utensils.
3. d. comma/but
My mom went to the grocery store, but she forgot her purse.
4. b. and
My apartment has 2 bedrooms and 1 1/2 bathrooms.
5. e. because
My daughter is having a birthday party because she is five years old today.
6. d. comma/ but
I would like to go to the movies, but my car does not work.
7. b. and
I have a computer and I have a printer.