Code dnt work. "cannot be resolved to a variable"

Question

In my Code there is Always the same Problem "lösung cannot be resolved to a variable"

And i have no other idea how to fix it.

I hope that someone of you can help me:

public static void main(String[] args)
{

// 1. Ausgabe
String chars = "abcdefghijklmnopqrstuvwxyzäöüß.,:;?-_()'=+/@";
Random rnd = new Random();
char buchstabe = chars.charAt(rnd.nextInt(chars.length()));

// Eingabe
Scanner scan = new Scanner(System.in);
System.out.println("Was ist der Morsecode von: " + buchstabe);
String antwort = scan.nextLine();
scan.close();

System.out.println(antwort);

// Berechnung der Lösung
if (buchstabe == 'a')
{
char lösung = '.';
}
else
{
System.out.println("False");
}

// Ausgabe
if (antwort == lösung)
{
System.out.println("True");
}
else
{
System.out.println("False");
}
}