Nuclear membrane is absent in

Volvox
Penicillium
Agaricus
Nostoc

The correct answer is D. Nostoc.

A nuclear membrane is a double membrane that surrounds the nucleus of a eukaryotic cell. It separates the nucleus from the cytoplasm and helps to protect the nuclear contents.

Volvox is a green algae that lives in fresh water. It is a colonial organism, meaning that it is made up of many individual cells that are connected together. Each cell in Volvox has a nucleus.

Penicillium is a fungus that is used to make penicillin, an antibiotic. It is a multicellular organism, meaning that it is made up of many individual cells. Each cell in Penicillium has a nucleus.

Agaricus is a mushroom that is edible. It is a multicellular organism, meaning that it is made up of many individual cells. Each cell in Agaricus has a nucleus.

Nostoc is a cyanobacterium that is found in soil and water. It is a prokaryotic organism, meaning that it does not have a nucleus.

Therefore, the correct answer is D. Nostoc.