Saying “OK”

Hi Nicholeen! My question today is about the instruction of saying ok when correcting. My daughter is clearly a rebel tendency and she struggles a lot with saying the word "ok" after we give her an instruction. My husband is definitely an upholder and insists she says the exact word, or else it doesn't count. I agree to a point, but I've noticed she responds better if she's given the choice to say ok either with "k", "uhuh", or using a playful tone she speaks with when she's happy and she says "ikey". She follows the instructions best when given the opportunity to choose how she says ok. So I'm wondering what your perspective is with this; is my husband's approach best, or mine, haha. Thanks you!