The key feature of a market system is
a. demand.
b. supply.
c. profit.
d. competition.

The answare  is D competition. I had this same question in my personal finance class.

Hope this helps!

Obviously she is under-stress and needs to cool down. she needs to slow down and take a break from her job, not completely, but ask for shorter hours until she finds enough time to study, pass, and work. if she can't get shorter hours, she can try making a day or two to study. she can work full time and get minimum wage but minimum wage can only get you so far in life.