I had marked option number 2 because the placental animals I thought were not due to adaptive radiation..
But the answer given is option 4.. can you please explain why?

Dear Student

Adaptive radiation is an evolutionary process that produces new species from a single, rapidly diversifying lineage. This process occurs due to natural selection.

Lemur is a placental mammal and spotted cuscus is a marsupial mammal and similarity in them points towards convergent evolution.
The similarities between placental mammals and Australian Marsupials point towards convergent evolution.

​​​​​​ Tasmanian wolf and tiger cat are both marsupials, placental mole and placental mouse are both placental mammals, Darwinian finches all these point towards divergent evolution i.e. under adaptive radiation.

Regards