**Core Concept**
Condyloma acuminatum, also known as genital warts, is a sexually transmitted infection caused by certain strains of the human papillomavirus (HPV). HPV is a large family of viruses, with over 100 types, and some of these types are specifically associated with the development of genital warts.

**Why the Correct Answer is Right**
Genital warts are primarily caused by low-risk HPV types, specifically types 6 and 11. These viruses infect the epithelial cells of the genital area, leading to the formation of warts. The exact mechanism of how HPV causes genital warts is not fully understood, but it is believed to involve the disruption of normal cell growth and differentiation. The presence of HPV types 6 and 11 is a hallmark of condyloma acuminatum, making them the primary causative agents.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because HPV types 16 and 18 are high-risk types associated with cervical cancer, not genital warts.
**Option B:** This option is incorrect because HPV types 2 and 4 are associated with skin warts, not genital warts.
**Option C:** This option is incorrect because HPV types 31 and 33 are also high-risk types associated with cervical cancer, not genital warts.

**Clinical Pearl / High-Yield Fact**
HPV types 6 and 11 are the most common causes of genital warts, and their presence can be confirmed through PCR or HPV DNA testing. Treatment options for genital warts include cryotherapy, imiquimod cream, and podophyllin resin.

**Correct Answer: D. 6 and 11**