John is working on determining the amount he should request for next year's advertising budget. He is having difficulty coming up with a reasonable figure. One of John's colleagues mentions that advertising budgets are typically determined in one of three ways. Which is NOT one of the three typical methods?

a$.$ The advertising budget is a percentage of last year's sales.

b$.$ The company spends approximately what it believes is parity with competitors.

c$.$ The company spends $10\%$ more on advertising than it did in the previous year.

d$.$ The company can use its strategic advertising goal $($e$.$g$.,$ enhance awareness or positiv attitudes$)$ and work backward to calculate necessary expenditures.