The specificity in IFN-α/β induced response comes from
The principle of core biological organization explains that structure-function relationships govern cellular processes. Hence A complex of IRF9, STAT-1 and STAT2 binding to ISRE sequence fits best because it integrates fundamental principles, as documented in authoritative sources on general biology.
Ref: Campbell et al., Biology, 11th Edition, Chapter 2, Chemical Basis of Life, discusses fundamental biological principles and molecular organization providing broad foundation for life sciences understanding.
