National defence is the correct answer because it is included in Union list.

**Answer:**

The subject that is not included in the state list is **b) National defence**.

The distribution of powers between the central government and state governments is divided into three lists: the Union List, the State List, and the Concurrent List. These lists specify the subjects on which each level of government has the power to make laws.

**1. Union List:**
The Union List consists of subjects on which only the central government has the power to make laws. Some of the subjects included in the Union List are defense, foreign affairs, atomic energy, banking, currency, and so on. National defense falls under the exclusive jurisdiction of the central government, and therefore it is included in the Union List.

**2. State List:**
The State List consists of subjects on which only the state governments have the power to make laws. Some examples of subjects included in the State List are police, public order, health, agriculture, irrigation, and so on. It is important to note that education is also included in the State List, contrary to the given options.

**3. Concurrent List:**
The Concurrent List consists of subjects on which both the central and state governments can make laws. Some examples of subjects included in the Concurrent List are criminal law, marriage and divorce, bankruptcy and insolvency, education, and so on.

Therefore, the correct answer is option **b) National defence** because it falls under the Union List, not the State List.