Ottoman architecture
was based entirely upon mughal models.
was the least impressive of ottoman artistic activities.
was based upon the pyramid structure of ancient egypt.
was the result of the work of architects and workers imported from outside the empire. used the open floor technique originally used in the byzantine church of santa sophia in designing mosques such as the one at edirne.

The answer is the last one. was the result of the work of architects and workers imported from outside the empire.

Explanation:

Though Ottoman architecture could be divided into several periods, the richest was the Classic period (1437 to 1703). Under the guidance of Mimar Sinan, the empire chief architect and civil engineer of 3 sultans, the Ottoman architecture saw a new era of harmonization and unification with several elements and influences that the empire had absorbed from different cultures. Taking a great deal from the Byzantine architecture, especially from the great and famous Hagia Sophia, they changed the proportions and designs. The interior of every structure was more open, with more light, giving emphasis to the contrast between lights and shadows and allowing a great volume of windows. Sinan started a new era in the entire world architecture, constructing over 300 buildings in several cities across the empire.

The correct answer is: Ottoman architecture used the open floor technique originally used in the Byzantine church of  Santa Sophia in designing mosques such as the one at Edirne.

Explanation:

Ottoman architecture was most influenced by the Middle East architectural styles. It emerged with the Ottoman Empire around the 14th-century, first in Iznik, and then in the two capitals of Bursa and Edirne to finally developed in Istambul. Sinan (1490-1588) was the most talented and renowned Ottoman architect. The Selimiye Mosque at Edirne, is one of his most celebrated creations. Ottoman architects were inspired by several types of architectural styles, like the Byzantine, Islamic and Iranian, but they adapted, modified and created their own complex and beautiful buildings. The open floor technique used in Selimye to display vast open spaces indoors, for example, was taken from the Byzantine church of Santa Sophia.

c) the invasion of the shang