For each of the questions below choose the number in the drop$-$down menu that correctly response to the multiple$-$choice question.

BE CAREFUL! The options will NOT be in alphabetical order!

A $15\%$ increase in production volume will result in a $$

A$.15\%$ increase in the variable cost per unit

B$.15\%$ increase in total mixed costs

C$.15\%$ increase in total administration costs

D$.15\%$ increase in total variable costs

A cellphone service provider charges $$5\mathrm{.}00$ per month and $$0\mathrm{.}50$ per minute per call. If a customer's current bill is $$65\mathrm{.}00,$ how many minutes did the customer use? $($Round any intermediate calculations and your final answer to the nearest whole minute.$)$

A$.130$ minutes

B$.140$ minutes

C$.120$ minutes

D$.110$ minutes