What is the name of the component of the Cyc system that allows databases and other external structured data sources to be treated as if part of the Cyc Knowledge Base?

a$.$ Integrating Semantic Sources of Knowledge $($ISSK$)$

b$.$ Knowledge Source Semantic Integrator $($KSSI$)$

c$.$ Semantic Knowledge and Understanding Integrator $($SKUI$)$

d$.$ Semantic Knowledge Source Integration $($SKSI$)$