She probably has a less chance of getting a job when all her kids are at school due to less time of job experiences when spending time with her children
Staying at home with the children is a time-consuming task (And is not a very "estimated" one)
Supposing that the school-age is around 5 or 6 years old, you can see that Maria will lose a lot of time with it, and her social life and career/job opportunities may suffer from it
It is probably A. It's like when I take melatonin before bed - doctors say to take it like 4 hours before bed but I take it 1 hour before I fall asleep and it works lol