If Science Is by Definition the Search for an Intelligible

Multiple Choice

If science is by definition the search for an intelligible network of natural cause-and-effect relationships, then it cannot admit to the possibility of a supernatural cause influencing the network in any way. (James E. Huchingson, "Introduction: The Two-Storied Universe," in James E. Huchingson, ed., Religion and the Natural Sciences: The Range of Engagement)
This passage exemplifies a(n) _____.

A) conditional statement
B) argument
C) explanation
D) unsupported assertion
E) illustration