Correct option is C
The described method involves driving a steel tube and shoe into the ground, filling it with concrete, and using upward extracting and downward tamping blows alternately. This process is known as the Vibro pile method. Vibro piles are installed using a vibrator to drive the pile into the ground, and in this case, the technique involves tamping and extracting.
Duplex pile: Involves a different method of installation.
Franky pile: Uses a different construction technique.
Mac Arthur pile: Also not related to the described method.
Therefore, the correct answer is (c) Vibro pile.
