Which of these closure expressions can be assigned to c?

{ Double($0) }{ x in Double(x) / 1.2 }{ $0 }{ $0 + $0 }

Great! The closure needs to return a Double-type value, which is why the Integer-type parameter needs to be converted.

Not quite! The closure needs to return a Double-type value, which is why the Integer-type parameter needs to be converted.