Sandra is selling brownies to save money for the French Club. The equation f (x)=0.5x-10 represents her profit, f(x), for selling x brownies. Which statement is true about the value of f(78)
A. the value f(78)=29 and it represents a profit of 29 dollars after selling 78 brownies
B the value f(78)=29 and it represents a profit of 78 dollars after selling 29 brownies
C The value f(78)=49 and it represents a profit of 49 dollars after selling 78 brownies
D the value f(78)=49 and it represents a profit of 78 dollars after selling 49 brownies