Ways to express gratitude

I really appreciate
your help!
Thank you,
I owe you (one)!
Yes, big time!/
You (really) do!
It was nothing!/
Don’t mention it!/
No problem

a) Professor – student:
Could you stay after the class?
b) Professor – student:
Could you explain the rule one more time?
c) 2 people on a street:
Can you show me the way to the supermarket?
d) Girlfriend – boyfriend:
Will you ever take me to the restaurant?