Circle the correct formula for marginal revenue $($MR$)$

a$.MR=19\mathrm{.}57-0\mathrm{.}44Q$

b$.MR=21\mathrm{.}74-0\mathrm{.}44Q$ c$.MR=26\mathrm{.}09-0\mathrm{.}44Q$

d$.MR=33\mathrm{.}33-0\mathrm{.}66Q$

e$.MR=30\mathrm{.}00-0\mathrm{.}4Q,f.MR=10\mathrm{.}71-0\mathrm{.}28Q$

a$.$ Price must fall but market quantity is indeterminate.

b$.$ Quantity must increase but market price is indeterminate.

c$.$ Price must increase but market quantity is indeterminate.

d$.$ Quantity must decrease but market p rice is indeterminate.

e$.$ Price must increase and Quantity must increase.

f$.$ Price must increase and quantity must decrease.