Generate a random number in a range based on dropdown item

I want to generate a random number in a range whenever a dropdown item is selected.

if (Dropdown.option = "small")
Debug.Log(random.range(10,100))
else if (Dropdown.option = "moderate")
Debug.Log(random.range(101,500))

I am currently only able to generate a random number when the value in the dropdown is changed.

public class Random_Pop : MonoBehaviour {

	Dropdown pop_Dropdown;

	// Use this for initialization
	void Start() {
		pop_Dropdown = GetComponent<Dropdown>();
		pop_Dropdown.onValueChanged.AddListener(delegate {
			DropdownValueChanged(pop_Dropdown);
		});
	}

	void DropdownValueChanged(Dropdown change) {
		Debug.Log(Random.Range(50, 150));
	}    
	}

I found a quick solution to this, but it’s not very elegant.

void Start() {
		pop_Dropdown = GetComponent<Dropdown>();
		pop_Dropdown.onValueChanged.AddListener(delegate {
			DropdownValueChanged(pop_Dropdown);
		});  
		
	}

void DropdownValueChanged(Dropdown change) {
		if (pop_Dropdown.value == 0) {
			Debug.Log("None Selected");
		} else if (pop_Dropdown.value == 1) {
			Debug.Log(Random.Range(10,50));
		} else if (pop_Dropdown.value == 2) {
			Debug.Log(Random.Range(45, 280));
		} else if (pop_Dropdown.value == 3) {
			Debug.Log(Random.Range(250, 755));
		} else if (pop_Dropdown.value == 4) {
			Debug.Log(Random.Range(735, 2500));
		} else if (pop_Dropdown.value == 5) {
			Debug.Log(Random.Range(1800, 8650));
		}
		//Debug.Log(Random.Range(50, 150));
	}