BE GOING TO VS. WILL

Hi..... friends help me ...

BE GOING TO VS. WILL

1) I feel very tired. I think I AAA to bed.
a) are going to go
b) will go
c) go
d) goes
my choice is a... But I have a doub ... please check

2) She has already decided. She CCC a new car.
a) 'll
b) be going to buy
c) is going to buy (my choice)
d) buying

3) I'm sure, you AAA (but B could work) the exam.
a) are going to pass (my choice)
b) will pass
c) will to pass
d) be going to pass

4) A: It's really cold in here.
B: Don't worry. I AAA (but C could work) the windows.
a) am going to close (my choice)
b) will to close
c) will close
d) are closing

5) A: What are your plans for the holidays?
B: I CCC to the beach.
a) will go
b) will to go
c) am going to go ( my choice)
d) going to go