The option type also prevents you from accessing the value if it's absent. Something a C union cannot do. Is there any example of options in an imperative language that would predate ML (which AFAIK introduced Some/None as the variants of option)?
Not that I'm disagreeing with you in any way, but it's worth recognizing that imperative languages typically do pattern matching and type constraining in a declarative manner. So one could make an argument that what you're saying is only true because imperative languages are not forbidden from employing FP. If a language uses declarative constructs, then it's not a wholly imperative language.
