Doubt in a multiple choice question involving cell organelles
I would say Nucleus is the odd one out. Chloroplast (which have Grana in them) and Mitochondria are involved in the process of creating/breaking down energy, whereas the Nucleus is, so to speak, the blue-prints of the cell. 

To summarize: 

Chloroplast is involved in Photosynthesis to create energy

Grana are in the Chloroplast, which is involved in Photosynthesis

Mitochondria are "the powerhouse of the cell" and help break down energy (ATP > ADP)

Nucleus is the cell's blue-prints

Therefore, it seems that the Nucleus is the least like the others.