Spawn enemy on nearest platform

Hi guys, i got a problem and i hope you guys will help me with a solution. i creating a game like doodle jump, so i am spawning a enemy, the enemy spawn just in a random place in air. i want i to spawn on a platform.

i want finalpostion to be equal to nearest platform position, every time the enemy spawns. heres the code: using UnityEngine; using System.Collections;

public class EnemySpawner : MonoBehaviour {

 public GameObject[] Enemy;

 public float MinTime = 2f;
 public float MaxTime = 20f;

 public bool spawning = false;

 public SpawnerScript1 pos;


 void Update()
 { 


     if (!spawning) 
     {
         StartCoroutine(SpawnEnemy());
     }
 }

 IEnumerator SpawnEnemy()
 {
     spawning = true;
     //Wait for random time before respawning
     yield return new WaitForSeconds(Random.Range(MinTime, MaxTime));
     //Set random position inside X&Y axis and materialize
     Vector2 finalposition = new Vector2(pos.position.x, pos.position.y - 1.2f);
     Instantiate(Enemy[Random.Range(0, Enemy.Length)], finalposition, Quaternion.identity);
     spawning = false;
 }

}