What is the result?

Given the code fragment:
String str = “Java is a programming language”;
ToIntFunction<String> indexVal = str: : indexOf; //line n1
int x = indexVal.applyAsInt(“Java”); //line n2
System.out.println(x);
What is the result?

A.
0

B.
1

C.
A compilation error occurs at line n1.

D.
A compilation error occurs at line n2.