Which proportion could be used to solve the problem below:
378 is 84% of what number?

A. [tex] \frac{84}{100} = \frac{378}{x} [/tex]
B. [tex] \frac{84}{100} = \frac{x}{378} [/tex]
C. [tex] \frac{378}{100} = \frac{x}{84} [/tex]
D. [tex] \frac{100}{84} = \frac{378}{x} [/tex]