Final answer:
Percy's mom is lost during the battle with the Minotaur as she seemingly dissolves into golden light, propelling Percy to defeat the beast.
Step-by-step explanation:
During the event where Percy defeats the Minotaur, Percy's mom is lost (option c). This occurs in the book 'The Lightning Thief' which is part of the 'Percy Jackson & the Olympians' series by Rick Riordan. When Percy, his mom, and his friend Grover are on their way to Camp Half-Blood, they are attacked by the Minotaur. In an intense confrontation, Percy's mom is seemingly dissolved into a shower of golden light after being grabbed by the Minotaur, leaving Percy devastated and fueling his determination to defeat the creature.