Rectangle A B C D has A B=6 and B C=3. Point M is chosen on side A B so that \angle A M D=\angle C M D. What is the degree measure of \angle A M D ?

**Answer Choices**

A. 15

B. 30

C. 45

D. 60

E. 75

Rectangle A B C D has A B=6 and B C=3. Point M is chosen on side A B so that \angle A M D=\angle C M D. What is the degree measure of \angle A M D ?

**Answer Choices**

A. 15

B. 30

C. 45

D. 60

E. 75