A furniture store sells kits that customers use to build cabinets. Each kit contains 18 screws and a set number of boards. Jarred buys 6 of these kits and has a total of 192 screws and boards. The equation shown represents this situation.

6(x + 18) = 192

What does the variable x represent in Jarred's equation?

A)the number of screws in all 6 kits
B)the number of screws in one kit
C)the number of boards in all 6 kits
D)the number of boards in one kit