Which programming training course is the easiest ?

It's not necessarily the easiest, but it IS the most logical. Learn C.

That will enable you to learn C++ which is, structurally-speaking similar to Java. You'll then find PHP easy.

The others are all different. HTML has been mentioned. This is both a coding scheme and a programming language. Early versions were mainly coding scheme, later versions, more of a programming language. HTML is easy to develop and test.

If you are writing mainly for the web, you have a choice of: Java, Javascript, PHP, Ruby, Python, Perl (I'd chose Ruby).

If you are writing freestanding applications, I'd chose C++