In order to determine if is a tautology, we make a truth table.

Since the statement contains three basic variables the truth table will require 8 rows. Since the statement contains 4 logical connectives, the truth table will require 4 columns in addition to columns for each of the basic variables, for a total of 7 columns. Notice how the columns for three basic variables are filled in in the truth table below. This is the standard configuration for a truth table with three basic variables.

Now we fill in each of the remaining columns:

Note that to fill in the last column, we must refer to the fifth and sixth columns.

The last column of the truth table shows that the statement is a tautology.