The correct answer is (c). Negotiation is not mentioned under Section 89 of Civil Procedure Code, 1908.
Arbitration, conciliation, and mediation are all modes of alternative dispute resolution (ADR) that can be used to settle disputes outside of court. Arbitration is a process in which the parties agree to submit their dispute to a neutral third party (the arbitrator) who will make a binding decision. Conciliation is a process in which the parties agree to meet with a neutral third party (the conciliator) who will help them to reach a settlement. Mediation is a process in which the parties agree to meet with a neutral third party (the mediator) who will help them to communicate and negotiate a settlement.
Negotiation is not a formal process and is not usually conducted with the assistance of a neutral third party. Instead, the parties themselves try to reach a settlement by discussing the issues in dispute and making offers and counter-offers. Negotiation can be a very effective way to resolve a dispute, but it can also be difficult and time-consuming.
Section 89 of the Civil Procedure Code, 1908, sets out the procedures for referring a dispute to arbitration. It does not mention negotiation, which suggests that it is not a formal process that is recognized by the law.