If one orange costs \( nx \), then the cost of \( y \) oranges would be:
\[ \text{Cost of } y \text{ oranges} = y \times (nx) = nxy \]
Looking at the options you've provided, none of them directly represent this cost. However, if we need to express \( nxy \) in terms compatible with the options, we can analyze the options based on what you have given:
- \( n(x-y) \) → This does not equal \( nxy \).
- \( n(x/y) \) → This does not equal \( nxy \).
- \( n(x+1) \) → This does not equal \( nxy \).
- \( n(x+y) \) → This does not equal \( nxy \).
- \( nay \) → This does not equal \( nxy \).
Given the lack of matching choices, it seems that there might have been an error in the options provided. The correct answer should be \( nxy \). Please verify the options or consult for further clarifications!