Please help me reset the BIOS administrator password.

Hi

Contact DELL, prove ownership and pay any fee requested.

Blue Oval "Get Help Now"

If it were a legacy Dell desktop pc and op is not bot then open the pc and reset password by passwd jumper on motherboard 

First post looks like an AI bot whereas we'll never hear from the OP again.

You can find manuals for your system here.

https://www.dell.com/support/home/en-us?app=manuals

Some Optiplex models have a jumper on the motherboard that will remove the BIOS Password.