○　正解です。

When someone asks for help the best way to reply is to say 'Of course', 'Yes' or 'Sure'.

For example :
A: Can you help me with my homework?
B: Sure.

If you can't help then the best way to answer is 'I'm sorry. I can't'
A: Can you help me this afternoon?
B: I'm sorry. I can't. I'm busy.

'No way' means 'No' but it is too strong. 'I'm sorry. I can't' is much more gentle.