Final answer:
The oldest known monumental sculpture is the Great Sphinx of Giza, which is 238 ft long and 66 ft high, and was built around 2550 BCE, representing Pharaoh Khafra.
Step-by-step explanation:
The world's oldest known monumental sculpture is the Great Sphinx of Giza. It measures 238 feet in length and 66 feet in height, and was built around 2550 BCE. The Sphinx features a head believed to be that of Pharaoh Khafra, who was interred in the second largest pyramid right behind the monument. Combining the head of a human and the body of a lion, it was hewn directly from the bedrock in a series of layers and represents one of the most iconic structures from Ancient Egypt. Located on the Giza Plateau, the Sphinx forms part of a complex that includes the three primary pyramids, which are the tombs of King Khufu, his son Khafre, and his grandson Menkaure.
Out of the options provided, the correct answer is d) Great Sphinx of Giza.