I want to get back to work after a 3-year break, but want someone to take care of my daughter. Should I call my mother or mother-in-law？

Asking the grandparents for help is the most logical way but it could also be the cause of many emotional disagreements. Firstly, you must consider whether or not they are free or willing to take care of your daughter. My parents have outwardly told me that they do not mind the occasional babysitting sessions but not full-time care because they don't think that they will be up to raising a child again. Secondly, if you leave your child in their care, how much power will you let them have -- the decisions and child rearing methods they are used to might not be something you'd agree with so it's important to consider that as well. There are probably other stuff to consider like finances and choosing between sides (if both are willing to take care of your daughter, who will you choose - your mom or MIL?). Personally, I would send my child to daycare just because it is the most neutral ground and I will be at ease that my child is in the hands of professionals (whom I can freely disagree with if I deem fit, and offer feedback if any) and that she will be in the company of other kids her age. I was raised by my grandparents and I have seen them disagree over how things are done haha and honestly, it was at times, confusing for me when my grandparents said okay to one thing and my parents said no.

Hi, if ur Mom or MIL are willingly ready to take care of ur daughter while ur at work than thats the best n ur mom would be better.other wise there are day care centers or u can hire a nanny too :)

You should first get inputs from Mother in law if she live's with you and second option should be Mother. Mother in law surly help with it as she enjoy take caring her grand children.

You can alternate with both as your daughter is both their granddaughter

Of cos Mother