В каком предложении должен стоять неопределенный артикль a/an?

- Аnn has got .... lemon.
- He likes.... butter and ....cheese for breakfast.
-..... jam and... milk is my favourite dish

В первом: Ann has got a lemon

-Ann has got a lemon.
-He likes butter and cheese for breakfast.
-Jam and milk is my favourite dish.
Неопределённый артикль не ставится на неисчисляемые предметы: jam, milk, cheese, butter. Не говорится "cheeses", "butters" или "jams".