"put your foot down" VS "put your feet down", which one is correct to say?
Here I listed out two sentences, which are similar to each other. Which sentence is correct to say?
A. You must reasonably make up your mind or put your foot down.
or
B. You must reasonably make up your mind or put your feet down.

I'd choose "A", but I am not sure! Therefore, please do me a fovor for making any firm confirmations!

Thank you in advance!

Question

"put your foot down" VS "put your feet down", which one is correct to say?
Here I listed out two sentences, which are similar to each other. Which sentence is correct to say?
A. You must reasonably make up your mind or put your foot down.
  or 
B. You must reasonably make up your mind or put your feet down.

I'd choose "A", but I am not sure! Therefore, please do me a fovor for making any firm confirmations!

Thank you in advance!

Answer

Put your foot down" is an idiom which means "be insistent and unwilling to compromise".

"reasonably make up your mind" has no clear meaning.

"put your feet down" has only its literal meaning.

Answer

You are correct.  Put your foot down is an expression meaning you are not changing your mind about something.