iMac reset gone terribly wrong!! Help asap!!

So i have a iMac i think 2010 model (im not sure) but i got it handed down and the person left their admin not logged out so considering i have no contact with this person i might as well factory reset the computer itself since ive done that before. Well big mistake because i had an issue with wifi and it whouldnt connect to it after i deleted the persons disk. So i decided to restart the computer itself and this screen popped up. I tried the restart method where you press the R button + command + shift but nothings been working. I tried to press on the options but the screen just keeps on going white and then back to square 1. Only option thats working is the one in the middle but i have 0 clue what to do there. Some1 please help asap 😭😭