Which of the following types of variances might be seen at the conclusion of a variance analysis?

Which of the following types of variances might be seen at the conclusion of a variance analysis? This is a quiz question, and my answers are:

a. rate, quantity and staffing

b. rate, volume and acuity

c. staffing quantity and quality

d. fixed budget, flexible budget, and acuity.

I am leaning towards b, rate, volume and acuity, but I am confusing it with a because if acuity is low, then the staffing variance will be bad