DNA is not present in Nucleus, Chloroplast, Ribosomes, Mitochondria

The nucleus is a house for chromosomal DNA, also called as nuclear DNA. Mitochondria and chloroplast are semiautonomous organelles that have single-stranded circular DNA. The ribosome is an assemblage of ribosomal RNA and ribosomal protein but does not contain its own DNA. Thus, the correct answer is option B.