A) Lie down is correct Not lay down because that means to put something down and it is a transitive verb that requires an object.. as in when I finish reading, I will lay down my book. Great question Diana Those 2 verbs are confusing. Thank you

A) Lie down is the right answer in terms of grammar Before this quiz I thought it was lay down. I had to look it up and now I understand the difference. Thank you Diana Interesting Quiz.

It depends on where you are from Lay down is used by some English speakers, particularly in the UK and the US, and it may be used in certain contexts in standard English too.