A. Simple
This is one independent clause so it is simple.
Compound is two independent
Complex is an independent and dependent
I don’t know what compound complex is but this sentence is simple
Answer:
However, he had laid a solid groundwork for others in their attempts to decipher the hieroglyphs.
Explanation:
i had the same question on one of my test and my teacher already graded it
I believe the best answer here is A. it uses imperfect coordinating structure.