Definition: In this task, you are given inputs i, j, and A, where i and j are integers and A is a list. You need to find all elements of A from the ith element to the jth element, reverse the order in which they occur, and then concatenate them to output the resultant string. i and j will be non-negative, and will always have a value less than the length of A. i will always be less than j. Perform the operations in order, i.e., do not concatenate the elements and then reverse the string.
Input: 6, 15, ['7417', 'a', '479', 'E', '1575', '6937', '4649', '9879', '9875', 'c', '1671', 'K', '3773', '6999', 'J', '9889', 'q', '4099', 'r', '1859', 'W']

J69993773K1671c9875987946496937