Final answer:
C. The first major government achievement during the Songhai Empire was the establishment of a professional army.
Step-by-step explanation:
The major government achievement that was the first of its kind during the Songhai Empire was c) the first professional army was established.
Askia the Great, a ruler of the Songhai Empire, strengthened the empire by expanding its territory and building a professional army. This army allowed the empire to conquer new lands, protect its trade routes, and maintain control over trans-Saharan trade.