There are several theories and models that are relevant to the field of Operations Research and Management Science. These theories and models provide frameworks and tools for decision-making, optimization, and problem-solving in various management scenarios. Below are some of the key theories and models that you should study for the Management optional subject:

1. Linear Programming:
- Linear Programming (LP) is a mathematical technique used to find the best possible solution for a given problem with linear constraints.
- LP involves maximizing or minimizing an objective function, subject to a set of linear constraints.
- The Simplex Method is a widely used algorithm for solving linear programming problems.

2. Queuing Theory:
- Queuing Theory is the study of waiting lines and the mathematical models used to analyze and optimize queuing systems.
- It helps in understanding the behavior of customers or entities in queues and helps in determining optimal resource allocation.
- Various queuing models, such as M/M/1, M/M/c, M/M/∞, etc., are used to analyze different queuing scenarios.

3. Inventory Theory:
- Inventory Theory deals with the management of inventory levels in order to minimize costs while meeting customer demand.
- Different models, such as Economic Order Quantity (EOQ), Just-in-Time (JIT), and Material Requirements Planning (MRP), are used to optimize inventory management.

4. Network Models:
- Network Models, such as Critical Path Method (CPM) and Program Evaluation and Review Technique (PERT), are used for project management and scheduling.
- These models help in identifying the critical path, determining project completion time, and managing resources effectively.

5. Decision Theory:
- Decision Theory provides a systematic approach for making optimal decisions under uncertainty or risk.
- Decision trees, utility theory, and game theory are some of the tools used in decision-making processes.

6. Simulation Modeling:
- Simulation Modeling involves creating computer models that mimic real-world systems to understand their behavior and make informed decisions.
- It helps in analyzing complex systems and evaluating different scenarios without the need for real-world experimentation.

7. Game Theory:
- Game Theory is the study of strategic decision-making in situations where the outcome depends on the actions of multiple players.
- It helps in understanding the interactions and strategies of different players and finding optimal solutions in competitive scenarios.

By studying these theories and models, you will gain a solid foundation in Operations Research and Management Science, enabling you to analyze and optimize various management scenarios effectively.