Solve the following proportion. Write the solution as a simplified proper fraction or mixed number when applicable.
(number1 / number2) / number3 = variable / number4
A) variable = (number1 * number4) / (number2 * number3)
B) variable = (number1 * number3) / (number2 * number4)
C) variable = (number2 * number4) / (number1 * number3)
D) variable = (number2 * number3) / (number1 * number4)