What does the error message "Cannot subset columns with a tuple with more than one element. Use a list instead." typically indicate in data manipulation tasks?
a) The operation attempted is not supported with tuples but requires a list to specify multiple columns.
b) The data manipulation tool does not support single-column operations.
c) The data is too large to handle with tuples and requires a different data structure.
d) The tuple format is incorrect and needs to be reformatted into a string.