1,2-diols are oxidised to ketones or aldehydes by periodic acid `HIO_(4)`. Periodic acid reacts with dipol to form a cyclic intermeditate. The reaction takes places because iodine is in a highly positive oxidation state, so it readily accepts electrons. When the intermeidate breaks down, the bond between the two carbon bonded to the OH group break.
Identify D.
A.
B.
C.
D.