Thank you for submitting homework task-2 in crypto-academy.

You can use any of the three keys to restore a wallet.

But do remember that the Keystore file alone is not equivalent to a Private key.

So if you are using the Keystore file to recover then you have to enter the password (set by you in the previous installation). If you are using Mnemonic key or Private Key then you don't need a password to restore a wallet.

Keystore File+Password(set by you) ~ Private Key

When you back up your Mnemonic/private key, the best practice is always to write it down on paper, and keep it safe, better break it into 3/4 parts and laminate it to make it durable.

Thank you.