Which of the following is not true about a scientific theory?

Science advances only through the scientific method.

We can come at this one via the process of elimination (in the true style of scientific investigation.)

A theory must explain a wide range of observations and experiments. This seems beyond doubt. It's obviously true.

Even the strongest theories can never be proved true beyond all doubt? This is true, because one can never observe ALL sets of natural phenomena which accord with a certain physical law. All we can say about a theory is that it's worked for all the time it's been observed.

Therefore, the first statement is the false one.

Hope this helps.

Thank you very much.  The way you explained it helped a lot.  Thanks once again.