You are the subcontractor on a large office renovation project responsible for installing energy efficient windows. The project baselines defines that the project will be completed in $7$ months with a total cost of the installation of $$450,000.$ After $4$ months, fifty percent of the work has been completed and $$240,000$ has been spent. What is the variance at completion?

A: $-$$$10,000$

B: $$30,000$

C: $-$$$30,000$

D: $$20,000$