Why are C#/.Net strings length-prefixed and null terminated?

Question

After reading What's the rationale for null terminated strings? and some similar questions I have found that in C#/.Net strings are, internally, both length-prefixed and nul

Answer 1

Here is an excerpt from Jon Skeet's Blog Post about strings:

Although strings aren't null-terminated as far as the API is concerned, the character array is null-terminated, as this means it can be passed directly to unmanaged functions without any copying being involved, assuming the inter-op specifies that the string should be marshalled as Unicode.