Maybe they just wanted to hear that LINQ was "Language-Integrated Query".
That being said, if they really want an explanation of "what" LINQ is comprised of, I would have probably included more information that you provided. Something like:
LINQ, or Language-Integrated Query, is a set of language additions and framework classes added in .NET 3.5 which enable a more functional approach to query operations. It's based upon extension methods for IEnumerable and IQueryable and their generic counterparts which allow deferred execution in LINQ to Objects and remote processing via IQueryable, as well as many other features. There were also language changes made to C# and VB.NET to support a more "natural" query syntax directly in the language.
