Who were the "Irreconcilables"?

A) Democrats who agreed to a set of compromises to prevent the Senate from rejecting the Treaty of Versailles.
B) Career diplomats who conducted a nationwide speaking tour to rally public support behind the Treaty of Versailles.
C) Senators who were determined to defeat the Treaty of Versailles with or without the Lodge reservations.
D) Wilson administration officials who were determined to prevent any concessions to opponents of the Treaty of Versailles.

The "Irreconcilables" were a group of senators who were strongly opposed to the Treaty of Versailles and the League of Nations. They were called "Irreconcilables" because they were considered to be unwilling to compromise on any issue related to the treaty, and were determined to defeat it in any form. They were primarily made up of Republicans, but also included a few Democrats. They were not willing to accept any compromises or reservations, and ultimately helped to ensure the defeat of the treaty in the Senate.