1.

"I really like your new haircut".

 giving a reason
  giving a compliment
  giving an excuse

2.

"You took $100 from my wallet!!".

 making a request
  making an accusation
  offering an apology

3.

"Sure, you can borrow my laptop".

 making a request
  declining a request
  giving permission

4.

"I can't lend you my bike today because I need it myself".

 offering an explanation
  declining an invitation
  accepting an invitation