OOP (Object Oriented Programming) Quizzes Object Class

Question:
Which method of string class in java is used to converts the boolean into String?

Option A):
public static String valueOf(double i)
Option B):
public boolean equals(Object anObject)
Option C):
public static String valueOf(Object obj)
Option D):
public static String valueOf(boolean i)

Correct Answer is Option D):
public static String valueOf(boolean i)