**Core Concept**
The treatment of hirsutism in PCOD involves hormonal regulation, particularly the suppression of androgen production and promotion of estrogen activity. This is achieved through the use of combined oral contraceptives (COCs), which contain estrogen and progesterone components.

**Why the Correct Answer is Right**
The combination of ethinyl estradiol (EE) and desogestrel (a third-generation progestin) is effective in treating hirsutism associated with PCOD. Desogestrel has a lower androgenic activity and higher anti-androgenic activity compared to other progestins, making it an ideal choice for hirsute women. EE, being a potent estrogen, helps in suppressing the production of androgens (such as testosterone) by the ovaries, thereby reducing hirsutism. The combination of EE and desogestrel also helps in regulating menstrual cycles and improving acne, which are common symptoms of PCOD.

**Why Each Wrong Option is Incorrect**
**Option A:** Ethinyl estradiol + Levonorgestrel is not the best choice for treating hirsutism in PCOD because levonorgestrel has moderate androgenic activity, which can exacerbate hirsutism.

**Option C:** Levonorgestrel alone is not sufficient for treating hirsutism in PCOD, as it lacks estrogenic activity, which is essential for suppressing androgen production.

**Option D:** None is incorrect because there are effective treatment options available for hirsutism in PCOD, and the combination of EE and desogestrel is a well-established and effective choice.

**Clinical Pearl / High-Yield Fact**
When choosing a treatment for hirsutism in PCOD, it's essential to consider the androgenic activity of the progestin component. Third-generation progestins like desogestrel have lower androgenic activity, making them a better choice for hirsute women.

**✓ Correct Answer: B. Ethinyl estradiol + Desogestrel**