The correct option is
C Like
Option D: 'Like' indicates comparison, by means of similarity. 'Like' means 'in the manner of', or 'in the manner characteristic of'.
Here, Galileo is described in the manner of a true scientist. Hence option D is correct.
Options A and B: 'For' and 'since' express purpose or reason.
Option C: 'Such' means 'very', and indicates a degree of something.
These words do not form a complete and meaningful sentence and hence options A, B and C are incorrect.