The top edge of the right-hand magazine page is missing. This removes:
Disposition: Preserve only visible text. Do not invent or silently reconstruct missing prose.
The source caption explicitly says Greg Hill had ended his one-man boycott of the ABA.
Answer: C. Greg Hill.
Published answer: True.
Historical evidence confirms that the ABA launched national Pro Cruiser competition in January 1981 and riders accumulated cruiser points during that season.
Cruiser racing itself existed before 1981. The archive therefore treats the quiz statement as referring to the 1981 Pro Cruiser points context, not the first existence of any cruiser class.
Supplemental source: https://nebraskabmxhalloffame.com/tim-lillethorup/
The source caption identifies Steve Johnson as Torker’s owner.
Answer: B. Steve Johnson.
The surviving top-edge fragment says:
… what he called a “Young.” JMC always did have the stylish riders, didn’t they?
The opening source sentence is cropped.
Answer: JMC.
Disposition: Label as contextual verification and preserve the source gap.
A period-article index identifies an ACS Z-Rim test from BMX Action featuring Trash Can Bob Morgan.
Answer: B. Bob Morgan.
Supplemental source: https://www.dreamgate.ne.jp/kuwahara/articles/article.html
The supplied article says Bell’s Moto III displaced Premier helmets and became the durable, desirable helmet used by the best.
Answer: Bell Moto III helmets.
The retained answer is:
D. Bob Morgan
The source’s upper aerial material and its identifying text are incomplete in the supplied spread.
Disposition: Retain the answer with a contextual-verification label. Do not manufacture a direct quotation from missing text.
The quiz transcription retains:
These are not silently modernized.
The known Renny Roker / Renny Rocker series issue does not occur in the supplied 1981 quiz or article.
Disposition: Do not carry the error into an unrelated year. Continue documenting it only where it appears in the published series.