The feasible region of a maximization problem shown is dertermined by

12x+5y<=180

5x+4y<=98

x^3 0, y=>0

which of the following objective functions has its maximum value at (15,0)? My answer is 9x+6y from a list of possible answers, is this right. If not please telll how to set this one up or graph. thanks so much for any help given.

a.z=25x+25y

b.z=9x+6y

c.z=20x+10y

d.z=45x+15y