Make an array stay the same when autofill (absolute reference)

Hi,

I have this array formula in E5:
{=SUM(C7:C47*E7:E47)}

I need to autofill from E5 up to the end of the row but only the E7:E47 array needs to change. The C7:C47 has to stay the same.

I tried
{=SUM($C7:$C47*E7:E47)}

but it gives me a VALUE error

How can I make the C array an absolute reference?

Please ignore this message

I fixed it by using

{=SUM($C$7:$C$47*E7:E47)}