Explain the basics of the concept of recursion.. 1. Consider the following data field and method. private intl] arr; // precondition: arr contains no duplicates, /7 the elements in arr are in sorted order, 10low high) return low; else if (arr [mid] num) return mystery (low, mid - 1, num); else return mid; II arr [mid]num What is returned by the call mystery(0, arr.length - 1, num)? (A) The number of elements in arr that are less than num (B) The number of elements in arr that are less than or equal to num (C) The number of elements in arr that are equal to num (D) The number of elements in arr that are greater than num (E) The index of the middle element in arr 2. Consider the following method /7 precondition: x 0 public void mystery (int x) System.out.print (x % 10); if ((x / 10)!-0) mystery(x 7 10); System.out.print (x % 10); Which of the following is printed as a result of the call mystery (1234)? (A) 1441 (B) 3443 (C) 12344321 (D) 43211234 (E) Many digits are printed due to infinite recursion