Syn dihydroxylation of alkenes Steps:

• Maleic acid contains a C=C double bond conjugated with carboxyl groups.
• Cold, dilute, acidified MnO4- adds two OH groups across the double bond in a syn manner.
• The symmetrical alkene receives OH on each carbon of the C=C.
• Resulting structure is HOOC-CH(OH)-CH(OH)-COOH, the cis-diol.

Why A is correct:

• A matches the product of syn dihydroxylation, where Baeyer's reagent hydroxylates alkenes without cleaving the C=C bond.

Why the others are wrong:

• B, C, D likely represent cleavage products or incorrect additions, as cold conditions prevent oxidative cleavage to CO2 or carboxylic acids.

Final answer: A