Basic (any form of basic language) is written using a C language. So it is obviously much slower than the former.
Completely wrong. Firstly, there is absolutely no need for any Basic language to be written in C. Secondly, even if it is, the language the compiler is written in is completely irrelevant to the quality of the compiled code. Thirdly, this very site happens to be home to several basic languages, all of which compile to machine language without compiling to C along the way, so C is in no way involved in the compiled code they generate.
Pascal / Delphi will always be slower than C, but it's still faster than most any Basic language.
The benchmarks above suggest this to be wrong also. For some reason you seem to think that the syntax of a language has anything to do with the speed of it, and that's just not right. Currently Delphi would appear to be slower than C and most modern variants of Basic, but it could just as easily be faster than both, because the syntax has very little affect on the speed of the compiled code.
These tests prove absolutely nothing IMHO.
Well on that we can agree. Unless you're writing the "count to a million in very small steps" game, benchmarking with a loop of double precision floating point variables tells you nothing worth knowing about the comparison between languages.