Volume variance

Misty Co’s budgetary control report for last month is as follows:

Fixed budget – 126,100 $
Flexed budget -130,855 $
Actual results – 133,580 $

What was the volume variance for last month?
A $4,755 (A)
B $2,725 (A)
C $4,755 (F)
D $2,725 (F)

Explanation: The volume variance for last month was $4,755 Adverse
The volume variance is the increase in cost resulting from a change in the volume of activity, ie the difference between the original budget and the flexed budget.
Volume variance = $126,100 – $130,855= $4,755 (A)

Why answer is A?

I think answer is C. Because when the volume of output is increasing it is favourable factor rather than adverse.

Thank you in advance for your help.