Which organelle in the cell, other than nucleus, contains DNA ?

Mitochondrion (option 4) is correct because mitochondria contain their own genetic material — small, typically circular mitochondrial DNA (mtDNA) present in multiple copies per organelle and inherited independently of nuclear chromosomes [1]. This feature is tied to their prokaryotic ancestry and endosymbiotic origin, which explains why mitochondria retain a genome and can replicate some components autonomously [1]. Other structures listed (centriole, Golgi apparatus, lysosome) do not harbour their own genomes; among eukaryotic organelles, only mitochondria and plastids/chloroplasts are known to contain DNA separate from the nucleus. Hence, mitochondrion is the only correct choice.

Sources

1. [1] https://www.khanacademy.org/science/ap-biology/heredity/non-mendelian-genetics/a/mitochondrial-and-chloroplast-dna-inheritance