'Cannot create an instance of an abstract class (Kotlin)

Trying to use LiveData but this error apears.

class GameViewModel : ViewModel() {
private val _score = MutableLiveData<Int>()
val score: LiveData<Int> = _score
private val _word = MutableLiveData<String>()
val word = LiveData<String> = _word


Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source