Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. It was the main programming language used by Apple for the OS X and iOS operating systems, and their respective application programming interfaces (APIs) Cocoa and Cocoa Touch prior to the introduction of Swift.

Based on that paragraph can we conclude that this sentence is true?
Objective-C is useful for many types of Operating Systems including iOS.
It's impossible to say