increment the value of a key in an object that corresponds to a key in Radis

i have one object in redis database that key is hello

there is one object in hello key for example:

{
  a: 'foo',
  b: 'bar',
  c: 0
}

I want to increment c in hello key of redis.

read this link Redis - String Incr Command, but this tutorial tells us how to increase the value of a radius key, not the value of a key in the object.