"This is not a menu."
Translation:Ce n'est pas un menu.
Why is "ce n'est pas une menu" worng ? Duolingo said that I had to use "carte".
"un menu" → menu is a masculine noun. It has suggested carte as you used the feminine indefinite article "une".
If you eat à la carte, you choose each dish from a separate list instead of eating a fixed combination of dishes at a fixed price