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]: 2, 3, ['5191', '9077', 'a']
[EX A]: a7709

[EX Q]: 3, 10, ['g', '5155', 'p', '6627', 'W', 'q', '2851', 'm', 's', '7781', 'u', '9739']
[EX A]: 1877sm1582qW7266p

[EX Q]: 4, 6, ['8353', 'V', 'a', 'e', '2241', 'X', 'D', 'X', '4249', '6471', '6311', 'n', '4791', '7821', '823', '4629', '929', '5077', '7701', '2317', '6183', 'U']
[EX A]:
X1422e