Doubt filling ds 160

[immihelp]

hi,

I was trying to fill DS 160 for my father.My fathers passport does not have surname. Instead they have written his full name in Given name column.

So when I tried to fill ds 160, I left Sur name as blank, but it does not allow me to save it.

Could you please help me on what to write in the sur name column.

Thanks

[immihelp]

Put that full name as last name and put FNU as first name.

[immihelp]

Hi,
Here the Sur Name is Blank, not the Given name.

1. Can I enter FNU for Sur Name?
2. Or do I enter Madhava Prasad Yezuvath as Sur Name and enter FNU for Given Name?
Attaching the passport copy. Could you please see that?

[immihelp]

I know all that, but you have to enter I said and not any other way.