Explanation:

Incorrect: Adenoviruses have double-stranded DNA genomes, whereas retroviruses have single-stranded RNA genomes. Retroviruses, such as HIV, replicate by first converting their RNA genome into a DNA intermediate via the enzyme reverse transcriptase.

Correct: The common cold can be caused by various viruses, and one of them is indeed adenoviruses. AIDS is caused by the Human Immunodeficiency Virus (HIV), which is a retrovirus.

Hence, the correct answer is "2 only"