IUPAC name of following compound is

• Identify the longest carbon chain containing the functional group: The longest carbon chain is four carbons long, indicating the prefix "butan-".
• Number the carbons in the chain: Begin numbering from the end nearest to the functional group. 
• Identify and name substituent groups: The amino group (–${\mathrm{NH}}_2$) is present as a substituent on carbon number 3. It is named as "amino".
• Identify the functional group: The functional group present is the nitrile group (–CN).

Combining all parts, the IUPAC name "3-Aminobutanenitrile" is derived.

Hence, the answer is option C.