A factor that differentiates a meta-analysis from a narrative literature review is that a meta-analysis:

A) focuses on effect size.
B) is more subjective.
C) summarizes what has been found.
D) is less accurate.

A meta-analysis focuses on effect size, which involves a statistical analysis of data to combine results from multiple studies. In contrast, a narrative literature review summarizes what has been found and may be more subjective in its analysis of the literature. Additionally, a meta-analysis is considered to be more accurate as it employs a rigorous methodology to identify and combine relevant studies.