This is harder than it needs to be because your source data is not one list and so you would need to nest different formulas for each month. Also, you haven't specified what happens when a fruit appears in more than one month.

I suggest you reformat your three lists to make a two column table like this
Fruit | Month
Apple | March
Fig | March

You will then find that VLookup becomes a lot easier and you can use a pivot table if you want to display the data like the way you presented it in your sample.

I would also recommend you learn about Index and Match from resources you can find online like this one

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Andrew Lockton
Chrysalis Design, Melbourne Australia