Organic Chemistry Problem: Using hot, conc., acidified KMnO4 on a compound

[asperity_1809]

A sample of L reacted with an excess of hot, concentrated, acidified potassium manganate(VII). Compound M is produced.
What could be the structure of compound L?

→ According to the answer key, the answer is A, i had picked B. I looked up the oxidation of alkenes with hot concentrated acidified KMnO4 solution but couldn’t really use the information from Chem libre text beyond the double bond between C atoms turning into ketone bonds.
I looked at my organic chem notes and acidified KMnO4 at room temperature oxidizes alkenes to diols while KMnO4 is also capable of changing alcohol to carboxylic acid, alkane to carboxylic acid and alkene to aldehyde/ketone.
I would like to know why the answer ISN’T B and what happened to change molecule L to M.

[Reza_Tamaddoni]

When we break op the double bond (red dashed line) by heated KMnO4 in acidic conditions, we normally induce carboxylic acid group on both carbons participating in the double bond if they are primary carbons (green 1^o).

If one of the double bond carbons is not primary, but secondary (have a side chain - green 2^o), then there will be a keton group induced on that carbon like in this question.

It is noteworthy to mention that answer options A and C have errors in my opinion. The double bond (not the one in the ring) must be noted with an oxygen symbol at the end like the molecule M itself. Therefore this question can be appealled if it appears like this in an IMAT exam.