Step 1: Understand the question.
The question asks which language group Kashmiri belongs to. Kashmiri is spoken in the Kashmir valley and has its own features. We check each group.
Step 2: Check option 1, Indo-Aryan.
Hindi, Bengali and Marathi are Indo-Aryan languages. Kashmiri is part of the wider Indo-Aryan family in some classifications, but the question asks for the specific group, and the closer group is Dardic. So this option is not the best answer.
Step 3: Check option 2, Dravidian.
Dravidian languages such as Tamil, Telugu, Kannada and Malayalam are spoken in the south. Kashmiri has no link with them. So this option is wrong.
Step 4: Check option 3, Austro-Asiatic.
Santali, Mundari and Khasi belong to this family and are spoken in central and eastern India. Kashmiri is not one of them. So this option is wrong.
Step 5: Check option 4, Dardic.
Kashmiri belongs to the Dardic group, spoken in the north west Himalayan region along with Shina and Kohistani. Many language lists place Kashmiri here. So this option is the best answer.
Step 6: Pick the answer.
The specific group of Kashmiri is Dardic, so option 4 is chosen. Note that Dardic is itself often counted inside the wider Indo-Aryan branch.
Final Answer:
Kashmiri belongs to the Dardic group of languages.
\[ \boxed{\text{Option 4}} \]