Answer:
Its C
Step-by-step explanation:
I would just divide 400 and 10 and then try to come up with the salary
how much did they sale? you can not complete the answer without a sale amount. because you are asking that they made $1,200 plus 3% of sale, but you do not have the amount they sold so it just $1,200+3% of the sale , but no number for how much they sale, but for advice i would get the total amount they sale and divide by 100 then times it by 3 then try to fill in the void on how they went from 1,200 to 2500. You need to tell us the amount they sold and then the we can answer your question, but without you will not get your answer, so your question is incomplete.
I think the answer is √20
let me know if I'm wrong. hope this helps
Equate whats inside (arguments) 
with base period of sine function 
and solve for x to get period,
So the period of the graph of the given function is precisely 2.
Hope this helps :)
