Qual o correto ?

a- They have to decide whether / if or not they are going to join us.

b- The German family is arriving this afternoon, and their / its car is already available.

c- It´s amazing how you look exactly like / as my uncle.

d- I will / am going to claim the refund right now...

e- Where were you ? I have been waiting / am waiting since early this morning.

f- He has been working like / as a dog since his baby was born.

g- I have seen / saw peter. He looks so different.