Question

which organelle is found in eukaryotic cells and contains
a nucleus
b endoplasmic reticulum (er)
c cell membrane
d ribosome

Explanation:

Eukaryotic cells have a defined nucleus which contains DNA. The endoplasmic reticulum is for protein and lipid synthesis, the cell - membrane is not an organelle but a boundary, and ribosomes are for protein synthesis and are not membrane - bound organelles that contain DNA.

Answer:

A. nucleus