What was the name of Cú Chulainn's grey horse?

Cú Chulainn’s grey horse was named Liath Macha. He was one of the hero’s two famous chariot-horses, paired with the black horse Dub Sainglend in the Ulster Cycle of Irish mythology.

The horses appear at the pool of Linn Liaith in the mountains of Sliab Fuait, where Cú Chulainn leaps onto them. They run around Ireland for a day but cannot throw him, after which they become tame. In later stories, they draw his chariot under the guidance of his charioteer, Láeg.

Liath Macha plays a particularly dramatic role in Cú Chulainn’s death. He refuses to let Láeg harness him, then submits only when Cú Chulainn approaches him. The horse weeps tears of blood, is wounded by Lugaid mac Con Roí’s second spear, and returns to the pool where he was first found.

The other names in the options are common traps: Dub Sainglend is the black companion, while Enbarr is a different magical horse associated with Manannán mac Lir.