A Rated-4 facility requires dual active utility feeds, each from an independent substation, but they may come from the same utility provider if substations are geographically separate and independent. * Option A is too strict; ANSI/TIA-942 does not mandate two different companies. * Options C and D do not provide true independence and would fail Rated-4 requirements. Thus, the minimum is two substations, possibly same provider. References: ANSI/TIA-942-B §6.2 (Utility Service Requirements).
