The Uninflated Cost of Dugout Brand Snow Shovels Currently Varies $( t = 0 )$

The uninflated cost of Dugout brand snow shovels currently varies from a high of $30 on January 1 $( t = 0 )$ to a low of $6 on July 1 $( t = 0.5 )$ . Assuming this trend were to continue indefinitely, calculate the uninflated cost $u ( t )$ of Dugout snow shovels as a function of time t in years. (Use a sine function.)

A) $u ( t ) = 15 \sin ( 2 \pi ( t - 0.75 ) ) + 3$
B) $u ( t ) = 12 \sin ( 2 \pi ( t - 0.75 ) ) + 18$
C) $u ( t ) = 18 \sin ( 2 \pi ( t - 0.75 ) ) + 12$
D) $u ( t ) = - 12 \sin ( 2 \pi ( t - 0.75 ) ) - 18$
E) $u ( t ) = 12 \sin ( 2 \pi ( t + 0.75 ) ) - 18$