$ sudo apt-get update
$ sudo apt-get install libjson-c2 

libjson-c2 is installed in your system.

Make ensure the libjson-c2 package were installed using the commands given below,

$ sudo dpkg-query -l | grep libjson-c2 *

You will get with libjson-c2 package name, version, architecture and description in a table

libjson-c2 package basic information: