Answer: #4 is wrong, the answer is "la"
#5 is not "la été" it's "l'été"
#6 both pizza and salade are feminine nouns so they are "la"
Explanation:
l' is used when the word after la or le starts with a vowel. Ex: oignon(onion), when you want to say "the onion" you don't write "le oignon" you write "l'oignon".
"la" is for feminine nouns
"le" is for masculine nouns
"les" is for plural and does not change because of the gender, it stays the same for both feminine and masculine nouns.
