HELLO MANU,
correct answer is methanal and its option A and the reason for this is i will explain below for you.
The iodoform test depends mainly on methyl(CH3 besides C=O) fragment being present ,since long this fragment gets converted into bright yellow iodoform precipitate and that is the signature of positive observation.
Since Methanal has the property of CH3 group it will give positive iodofrom test and no other compound have this property above given
and with respect to fehlings test
Whem Methanaldehyde on warming with the fehlings solution gives red precipitate of copper oxide and this indication gives you that methanal will give both positive test for iodoform as well as fehings test
THANK YOU
