Doubt from HIO4 reaction

Answer is given as Option C.

How can periodic acid oxidise compound 4,5 ?

I thought it could oxidise everything except compounds 4 and 5.

And also I thought it couldn't oxidise compound 6

@Shwetanshu_2018 bhaiya can you take a look at this ?

All of these can undergo oxidation

Replacing OH with NH2 will make no difference, still it will be oxidised


All of these can’t go oxidation

But why can't I replace 'double bonded O' with 'two -OH' and perform the oxidation?

@deep_2020 I didn’t get your question .
Can you please draw the structure and explain your question

I meant something like this.