**Core Concept**
Low-dose oral contraceptive pills (OCPs) contain a combination of estrogen and progestin at lower doses compared to traditional OCPs. This reduction in dose was made to minimize side effects while maintaining contraceptive efficacy.

**Why the Correct Answer is Right**
Low-dose OCPs typically contain 20-35 micrograms of ethinyl estradiol (EE), a synthetic form of estrogen. The progestin component is usually a second-generation progestin, such as norgestimate or norethindrone. The combination of lower estrogen doses with second-generation progestins has been shown to reduce the risk of thrombosis and other estrogen-related side effects while maintaining contraceptive efficacy.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incomplete and does not provide any information about the content of low-dose OCPs.
**Option B:** This option is incorrect because it does not specify the type of estrogen or progestin used in low-dose OCPs.
**Option C:** This option is incorrect because it does not provide any information about the estrogen content of low-dose OCPs.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that low-dose OCPs are not suitable for all patients, particularly those with a history of thromboembolic events or migraines with aura. The decision to prescribe low-dose OCPs should be made on a case-by-case basis, considering the patient's individual risk factors and medical history.

**Correct Answer:** C. 20-35 micrograms of ethinyl estradiol (EE) in combination with a second-generation progestin.