Jabari owns 100 shares of stock a and 45 shares of stock b. for the past month, his stocks have been fluctuating inversely. stock a decreased by  m  cents per share and stock b increased by  n  cents per share. which equation can be used to find the total change in value of jabari's shares per month?
a: v=(100•-m)+(45•n)
b: v=(100•m)+(45•n)
c: v=100(4•-m)+45(4•n)
d: v=145(-m•n)