Final answer:
The Rift Herald spawns at 14:00 into a League of Legends match and can respawn once, allowing for a maximum of two spawns before it despawns permanently.
Step-by-step explanation:
The Rift Herald in League of Legends spawns at 14:00 (minutes) into the game. It can respawn only once after being defeated, provided it is killed before the 19:45 mark, or before the 19:55 mark if the Herald has not been aggroed by that time. This means the Herald can potentially spawn a total of two times before despawning permanently. Hence, none of the options A, B, C, or D provided are correct based on the game's current mechanics as of the knowledge cutoff in 2023.