Defense of the nation is a service provided by our armed forces. This service is.

1. Non -Public good which is non-rival and non excludable in consumption.
2. Public good which is non-rival and non excludable in consumption.
3. Non -Public good which is rival and non-excludable in consumption.
4. Public good which is rival and non-excludable in consumption.

Option 1 -> Incorrect classification - defense cannot be a non-public good when it has non-rival and non-excludable characteristics.

Option 2 -> Correct classification - defense is a public good because it exhibits both non-rivalry and non-excludability.

Option 3 -> Incorrect - defense is not rival in consumption; one person's protection doesn't reduce another's.

Option 4 -> Incorrect - public goods cannot be rival; this is a contradiction in terms.

Hence, Option 2: Public good which is non-rival and non-excludable in consumption -> National defense is the classic example of a pure public good. It is non-rival because one citizen's protection does not diminish the protection available to others - the entire nation is defended simultaneously. It is non-excludable because it is impossible to protect some citizens from external threats while excluding others. These two characteristics (non-rivalry and non-excludability) are the defining features of public goods, which is why governments typically provide defense services rather than private markets. -> correct