Three of the following statements are comma splices. Choose the one correctly punctuated statement that is not a comma splice.

• a) America's teacher-shortage problem is not improving, additionally, many current teachers would not recommend careers in education.

• b) America's teacher-shortage problem is not improving, moreover, many current teachers
would not recommend careers in education.

c) America's teacher-shortage problem is not improving, many current teachers would not recommend careers in education.

• d) America's teacher-shortage problem is not improving. In addition, many current teachers would not recommend careers in education.