**Core Concept**
In a dichorionic diamniotic (DiDi) twin pregnancy, each fetus has its own placenta and amniotic sac. Managing breech presentation in one twin and cephalic presentation in the other requires a careful approach to minimize risks and optimize outcomes.

**Why the Correct Answer is Right**
For a DiDi twin pregnancy with a breech-presenting twin and a cephalic-presenting twin, the recommended management is to plan a cesarean delivery (C-section) for both twins. This is because a breech presentation in one twin increases the risk of complications during vaginal delivery, such as umbilical cord prolapse or fetal distress. A C-section allows for a controlled delivery of both babies, minimizing the risk of complications.

**Why Each Wrong Option is Incorrect**
**Option A:** Vaginal delivery of the breech-presenting twin followed by vaginal delivery of the cephalic-presenting twin. This approach is not recommended due to the increased risk of complications during vaginal delivery of the breech-presenting twin.

**Option B:** External cephalic version (ECV) to convert the breech-presenting twin to a cephalic presentation. ECV is not typically recommended in twin pregnancies, as it may not be successful and can increase the risk of complications.

**Option C:** Vaginal delivery of the cephalic-presenting twin followed by vaginal delivery of the breech-presenting twin. This approach is not recommended due to the increased risk of complications during vaginal delivery of the breech-presenting twin.

**Clinical Pearl / High-Yield Fact**
In DiDi twin pregnancies, a breech presentation in one twin increases the risk of complications during vaginal delivery. A C-section is often recommended to minimize these risks and optimize outcomes.

**Correct Answer:** C. Cesarean delivery of both twins.