Sample Questions: Java SE 5 and 6, Certified Associate (1Z0-850)

Option A is incorrect because the - operator is NOT valid on string arguments.
Option B is incorrect because there is no remove method in the String class.
Option C is incorrect because there is no subtract method in the String class.
Option D is correct because the replace method removes the character sequence in the first argument and replaces it with the character sequence in the second argument.