Lenoir Cycle:
The Lenoir cycle is a thermodynamic cycle that describes the operation of a reciprocating internal combustion engine. It consists of the following processes:

1. Constant Volume Heat Addition:
In the Lenoir cycle, the first process is constant volume heat addition. During this process, the fuel-air mixture is ignited and combustion occurs at a constant volume. The heat released during combustion increases the temperature and pressure of the working fluid.

2. Reversible Adiabatic Expansion:
After the constant volume heat addition, the working fluid undergoes a reversible adiabatic expansion. This expansion is characterized by a decrease in pressure and temperature of the working fluid. The expansion is adiabatic, meaning there is no heat transfer during this process.

3. Constant Pressure Heat Rejection:
The third process in the Lenoir cycle is constant pressure heat rejection. During this process, the working fluid is cooled at a constant pressure. Heat is transferred from the working fluid to the surroundings, causing a decrease in temperature and pressure.

Explanation:
Among the given options, the Lenoir cycle is the only one that consists of a constant volume heat addition, reversible adiabatic expansion, and constant pressure heat rejection. Let's analyze the other options to understand why they are not the correct answers:

- Otto Cycle: The Otto cycle consists of constant volume heat addition, reversible adiabatic expansion, and constant volume heat rejection. Therefore, it does not match the description given in the question.

- Atkinson Cycle: The Atkinson cycle is an extension of the Otto cycle and also consists of constant volume heat addition, reversible adiabatic expansion, and constant volume heat rejection. Therefore, it does not match the description given in the question.

- Brayton Cycle: The Brayton cycle consists of constant pressure heat addition, reversible adiabatic expansion, and constant pressure heat rejection. Therefore, it does not match the description given in the question.

Based on the analysis above, the correct answer is option 'B' - Lenoir cycle, as it is the only one that matches the given description of the cycle consisting of constant volume heat addition, reversible adiabatic expansion, and constant pressure heat rejection.