Johannah has $\$50$ for soda and she needs to buy both diet and regular soda. Her total order must have at exactly 2 times as many cans of diet soda as cans of regular soda. What is the greatest number of cans of diet soda can she can buy if regular soda is $\$0.50$ per can and diet soda is $\$0.75$ per can?

Question

$\begin{array}{1 1} a) \text{Diet soda=25 and regular soda=50} \\ b)\text{Diet soda=50 and regular soda=25} \\ c) \text{Diet soda=15 and regular soda=30} \\ d)\text{Diet soda=30 and regular soda=15} \end{array} $