Out of the given options, choose the sentence, which, in your view, is the most grammatically and structurally correct. Please note that the meaning or the context of the sentence must not change.
Out of the given sentences, the only correct sentence is given by option 4.
None of the other sentences are grammatically sound.
The forms 'must succeeds', 'must to succeed' and 'is must to succeed' are grammatically incorrect.
Therefore, the correct answer is option 4.