Mrs. Dyson works at a music camp. She has $90 to spend on guitar strings for her students. A pack of bronze strings costs $6.00. A pack of nickel strings costs $4.50. The following equation represents her situation.

6x + 4.5y = 90

How can you use the equation to find the total number of packs Mrs. Dyson can buy if she only buys nickel strings?

A. Substitute 0 for X and solve for Y. C. Substitute Y for X and solve for Y.
B. Substitute 0 for Y and solve for X. D. Substitute X for Y and solve for X.