changing multiple gameobjects in script

I have four gameobjects into my scene and i want to change the sprite renderer’s color of each game object based on an input. Ex: if “q” is down change the first game object color to green then check if the key isnt pressed anymore so it goes back to normal. Do that for the 3 other game objects but with different inputs. “w” for the 2nd one, “o” for the 3rd one and “p” for the 4th one. I already made the code to detect the input and change the color. But it does it for all of the gameobjects and not a specific one. How can i change a specific gameObject from my scene without having to make a different script for all of the gameObjects?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class NewBehaviourScript : MonoBehaviour
{
    SpriteRenderer sr;
    Color sr_NewColor;
    float sr_Green, sr_White;

    // Start is called before the first frame update
    void Start()
    {
       sr = GetComponent<SpriteRenderer>(); 
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetKeyDown("q"))
        {
           sr.color = Color.green;
        }

        if (Input.GetKeyUp("q"))
        {
           sr.color = Color.white;
        }
    }
}

Well…

If all objects hae this script, all objects will do the same… of course… Make one different script for each object with dfferent Key detection

Os make one general script and changing only the render of the object you want…

Recomendation:

Go look for tutorials about reaching variables and components of diferent objects

Bye