C isn’t really an option. Elrond and Isildur were never near Orodruin for him to cast it in as an option. Isildur claimed it after he cut it from Sauron’s hand.

My answer would be D too.

I remember reading or listening to a short story where the author described what would’ve happened if Elrond had pushed Isildur into the fire in order to destroy the ring. If I remember correctly Elrond emerges from mount doom and eventually communicates what happened at the peak and his action of killing Isildur in order to destroy the ring, this ends up angering the humans who would later start a war with the elves in order to avenge the death of Isildur. This leads to massive casualties on both the human and elven side but the war abruptly stops as a massive rain suddenly appears and lasts for many many days, flooding the world and destroying it. Finally, it is revealed that the rain was caused by the tears of Illuvatar being shed over the terrible slaying of his children amongst themselves.

https://www.youtube.com/watch?v=P68HWtN4zG8

In Deep Geek always has the deep answers to LotR questions like this.