Which of the following is an example of monumental architecture?

A. mud-brick house

B. stela

C. ziggurat

D. seed plow

The answer is C: ziggurat. A ziggurat is a Mesopotamian temple and were generally very large, showing off genuine Mesopotamian architecture. A mud-brick house isn't exactly monumental, a stela is a slab of stone, and a seed plow is a farming tool.