Formula for Different Calculations within one cell

I am attempting to determine spending, depending on the project status. I thought maybe the IF THEN formula would help, but I kept receiving errors when writing the formula.

Project (Column A)

Status (Column B)

Cost (Column C)

Spent (Column D)

Based on the status provided in Column B, I'd like Column D to calculate Column C differently. For Example, if the status is "Planning", then Column D should take the Column C*0. If the status is "Pre-Production"=Column C*0.5, "Production"=Column C*0.7, "Completed"=Column C*1

Answers