Give a reason

[Bassim]

I have used "give a reason" in my sentence, but I am not sure if it is correct. Would you please correct my mistakes?

I imagined Peter coming home from school and saying to his mother that his teacher treated him harshly lately.
And mother asks, "Did you give him a reason for that?"

Or should I write: "Did you give him a cause for that?"

 

[GoesStation]

I imagined Peter coming home from school and saying to his mother that his teacher had been treating [STRIKE]ed[/STRIKE] him harshly lately.
[STRIKE]And[/STRIKE] His mother asks, "Did you give him a reason for that?"

It might be more natural for his mother to ask "Did you give him a reason to do that?"

 

[Tdol]

And mother asks, "Did you give him a reason for that?"

This doesn't work for me, but GoesStation's version does.