The correct option is
B Superficial
The given word 'shallow' means 'lacking depth', 'being superficial'.From the options, Option B: 'superficial' best expresses the meaning of the given word. Hence option B is correct.
Option A: 'Natural' is 'something that is formed by nature'.
Option C: 'Foolish' means 'showing lack of sense or wisdom'.
Option D: 'Worthless' means 'of no worth or importance'.
These words do not mean the same as the given word, hence options A, C and D are incorrect.