Option c is the correct answer. Kaaba is a sacred building that is located in the center of the Masjid al-Haram or the Grand Mosque in Mecca, Saudi Arabia. The Kaaba is the most sacred site and the direction of prayer for Muslims all over the world. The Kaaba is a cube-shaped structure that is covered with a black cloth called the kiswah. It has a gold-embroidered band and a door on one side. Inside the Kaaba, there are three pillars, a marble floor, and several religious objects. The most notable object is the Black Stone, which is a meteorite that is embedded in one corner of the Kaaba. The Black Stone is believed to be a relic from the time of Adam and Eve, and Muslims kiss or touch it as a sign of reverence.