**Core Concept**
A trial of normal labour after caesarean section (TOLAC) is a procedure where a woman who has had a previous caesarean section attempts to deliver vaginally. The decision to proceed with TOLAC depends on various factors, including the type of previous uterine incision, the presence of any previous uterine scars, and the overall health and well-being of the mother and baby.

**Why the Correct Answer is Right**
The correct answer is **B. Previous classical uterine incision**. A classical uterine incision, also known as a vertical incision, is a type of uterine incision that extends from the top to the bottom of the uterus. This type of incision is a contraindication for TOLAC because it increases the risk of uterine rupture during labour, which can be life-threatening for both the mother and the baby.

**Why Each Wrong Option is Incorrect**
* **Option A:** Previous low-transverse uterine incision is not a contraindication for TOLAC. In fact, this type of incision is often considered safe for TOLAC, as it is less likely to rupture during labour.
* **Option C:** Previous multiple uterine scars are a relative contraindication for TOLAC, but not an absolute contraindication. The decision to proceed with TOLAC in this case would depend on individual risk assessment and careful evaluation of the mother's overall health and well-being.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that a previous classical uterine incision is a contraindication for TOLAC, and any woman with a history of this type of incision should be advised against attempting a vaginal delivery.

**Correct Answer: B. Previous classical uterine incision**