input: Write a python function to retrieve a specific element from a 2D array given the row and column indices.
  assert retrieve_element([[1,2,3],[4,5,6],[7,8,9]], 2, 0) == 7
  assert retrieve_element([[10,20],[30,40]], 1, 1) == 40
  assert retrieve_element([[5,15,25],[35,45,55],[65,75,85]], 0, 2) == 25
output: def retrieve_element(array, row, col):
      return array[row][col]