The term network clearance refers to

The term network clearance refers to
 
  a. a station's agreement to air a network program in a specific time slot
  b. a network's agreement to empty certain hours so that affiliates can fill them with syndicated or local shows
  c. a station's commitment to air a network program, usually within a few hours or days of delivery
  d. contractual agreements by all 200+ affiliates of one network to air a specific program in a specific daypart
  e. contractual agreements by all 200+ affiliates to air 90 percent of their network's total schedule