Try the first table value and see what you get from the various choices. For x = 1, the answer choices give you
... A: y = 5×1 = 5
... B: y = 1 + 1 = 2
... C: y = 1 + 2 = 3
... D: y = 2×1 = 2
Both B and D give the correct value (2), so we need to try another table entry. For x = 3 (the second table entry), the answer choices give you
... B: y = 3 + 1 = 4
... D: y = 2×3 = 6
Only selection D gives you the correct value (6). The appropriate choice is
... D. y = 2x