The Following Question Are Based on the Following Diagram

The following question are based on the following diagram:

-Suppose a sales tax on the commodity is imposed where S and D are the market supply and demand curves before the tax was levied.The equilibrium price with the tax is

A) $6.
B) $6.40.
C) $7.
D) $7.40.
E) somewhere between $6.40 and $7.