Answer:
The correct answer is - mihrab.
Step-by-step explanation:
Mahrib or mihrab is a semicircular niche appear the wall that is known as the qibla wall of a mosque that indicated the direction of the Mecca so mushlim can face towards the mecca when praying.
Mihrab is an essential architecture of a mosque as no matter where is a mosque, mihrab always indicate the direction of Mecca (kabba).
Thus, the correct answer is - mihrab.