I am trying to get the title on the header on my react native application. i have been following a video lecture, but I till can't seem to get it right

import { StyleSheet, Text, View } from 'react-native'
import React from 'react'
import { DOC } from '../Data/dummy-data'

const Doctors = props => {
  
  // destructure
  const { docId } = props.route.params

  const selectedCategory = DOC.find(doc => doc.id === docId)
  return (
    <View style={styles.screen}>
      <Text>{selectedCategory.title}</Text>
    </View>
  )
}

Doctors.navigationOptions = (navigationData) => {
  const docId = navigationData.navigation.getParam('docId')
  const selectedCategory = DOC.find(doc => doc.id === docId)

  return {
    headerTitle:selectedCategory.title
  }

}

export default Doctors

const styles = StyleSheet.create({
  screen:{
    flex:1,
    justifyContent:'center',
    alignItems:'center'
  }
})