How to make first picker view row unselectable

Hi to you all, I am new in iOS development and in a making of an app. I am using uitextfield connected with uipickerview in the home screen. Is there somehow a way to make it when I choose the text field the picker view to popup with the first option whitch is (lets say...) "--" whitch is unchoosable. And 2 other options whitch when clicked take me to to other view controllers.

This is my code:

import UIKit

class ViewController: UIViewController {

Code Block 
let options = ["--", "option 1", "option 2"]
var identities = [nil, "table_vc_teacher", "table_vc"]
@IBOutlet weak var optionsField: UITextField!
var picker = UIPickerView()
@IBAction func didTuchBtn(_ sender: Any) {
		let vc = storyboard?.instantiateViewController(identifier: "table_vc") as! TableViewController
		vc.navigationItem.largeTitleDisplayMode = .never
		navigationController?.pushViewController(vc, animated: true)
}
override func viewDidLoad() {
		super.viewDidLoad()
		
		picker.delegate = self
		picker.dataSource = self
		
		optionsField.inputView = picker
		optionsField.textAlignment = .center
		optionsField.placeholder = "Избери Програма"
}

}


// Picker View
extension ViewController: UIPickerViewDelegate, UIPickerViewDataSource {

Code Block 
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
		return options[row]
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
		return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
		return options.count
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
		if (row == 0) {
				
		}
		
		optionsField.text = options[row]
		optionsField.resignFirstResponder()
		
		let vcName = identities[row]
		let viewController = storyboard?.instantiateViewController(identifier: vcName!)
		viewController?.navigationItem.largeTitleDisplayMode = .never
		self.navigationController?.pushViewController(viewController!, animated: true)
}

}


The "var identities" are the storyboard identifiers for my other view controllers (This was from a video for table views but I toth to implement them in this code here). I am asking the question for a new ideas on how to make my code doing the stuff I described at the start.

I really need help! Please!

Code Block 
				
		} else if row == 1 {
				let vcOne = storyboard?.instantiateViewController(identifier: "table_vc_teacher") as! TeacherViewController
				vcOne.navigationItem.largeTitleDisplayMode = .never
				self.navigationController?.pushViewController(vcOne, animated: true)
				
		} else if row == 2 {
				let vcTwo = storyboard?.instantiateViewController(identifier: "table_vc") as! TableViewController
				vcTwo.navigationItem.largeTitleDisplayMode = .never
				self.navigationController?.pushViewController(vcTwo, animated: true)
				
		}