Who constructed Qutub Minar

Explanation:
Discovered Inscriptions tell us that the construction of Qutub Minar was begun by Qutub-ud-din Aibak in 1198 and completed by his successor Iltutmish in 1215, although the two upper tiers were rebuilt in later periods.
The red sandstone is the primary material used to construct Qutub Minar.

Final Answer:
Hence, the correct answer is option C. i.e., Qutbuddin Aibak.