Clear this computer's TPM (Trusted Platform Module)

I was resetting my Windows 10 Dell 5559 laptop to factory Setting.

got this message after screen had stuck on 99% during reset the message displayed is

"A configuration change was requested to clear this computer's TPM (Trusted Platform Module)

WARNING: Clearing erases information stored on the TPM. You will lose all created keys and access to data encrypted by these keys.

Press F12  to clear the TPM Press ESC  to reject the change request and continue"

I just don't know whether to press F12 or ESC?

 I have recently bought this laptop .

Regards

Sanal.P