Explanation:

- Igneous rocks are typically classified into two major types based on their formation: intrusive and extrusive.

- Intrusive igneous rocks (also called plutonic) form beneath Earth's surface when magma cools slowly, resulting in coarse-grained textures. Granite is a classic example.

- Extrusive igneous rocks (also known as volcanic) form at or above Earth's surface from lava, cooling rapidly to produce fine-grained textures. Basalt and pumice are examples.

- Option:1, Four - Incorrect as only two primary types are widely recognized, though there are subtypes.

- Option:2, Six - Incorrect and redundant, as main types are two.

- Option:3, Two - Correct; igneous rocks are mainly categorized into intrusive and extrusive.

- Option:4, Five - Incorrect for the same reasons.