Twice as old as" means we will be multiplying by 2. "her cousin" - we need a new variable C to represent her cousin's age. "was three years ago" - 3 years ago means we will have to subtract 3.
The option which is not one of the five vegetable categories is C. leafy.
Here are the five vegetable categories:
1. dark-green: broccoli, spinach, kale...
2. red and orange: tomatoes, carrots, squash, pumpkin, sweet potatoes...
3. beans and peas
4. starchy: corn, potatoes, green peas...
5. other: zucchini, peppers, Brussel sprouts...