In this task, you are given inputs 'i', 'j', and A, where 'i' and 'j' are integers and A is a list. A list is shown by two brackets and comma-separated numbers and characters inside, like ['1', '12', 'l']. You need to concatenate all elements of A from the ith element to the jth element, and then reverse the resulting 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 reverse first and then concatenate.

[EX Q]: 14, 20, ['9977', 't', 'Y', 'i', '7981', 'a', '1711', '3371', '9143', '3665', '1525', 'y', 'b', '379', 'k', 'T', 'Q', 'D', 'c', '1001', '551', 'Z']
[EX A]: 1001cDQTk973

[EX Q]: 2, 3, ['T', '9003', '3731', '287', '7101', 'm', '2147', '6123', '6319']
[EX A]: 13733009

[EX Q]: 2, 17, ['4685', '6663', '8313', '3433', 'W', '8515', '8451', 'F', 'Z', '751', '93', 'd', '1535', 'A', 'P', 'P', '1173', '6565', '6007', '8815', '5479', '6923']
[EX A]:
3711PPA5351d39157ZF15485158W334331383666