4: d) Write a program to print out the following: 1 2 12 3 1234 12345678910 9 marks) b) What is the output of the following program. public class Testf public static void main(String argsD 1 StringBuffer sb-new StringBuffer("abcdef); sb.replace(0, 3, "xyz"); System.out.println(sb); sb - new StringBuffer("abcdef'); sb.replace(sb indexOf("abc"), sb.indexOff"def), "lmo"); System.out.println(sb): 3 )