Answer
Spinach is an inferior good.
Popeye's demand curve for Spinach would shift to the right.
Work Step by Step
In general, there are two types of goods in the context of income: normal goods and inferior goods. Normal goods are goods for which the demand increases as income increases, and vice versa. Inferior goods are goods for which the demand decreases as income increases, and vice versa. Since we know that Popeye purchases more spinach as his income goes down, spinach must be an inferior good for him. As a result, we know that his demand for spinach will increase (his demand curve will shift to the right) in response to his decrease in income.
