If the distance b A. 5

B. ± 5

C. – 5

D. none of these

Let P be the point whose coordinate is (a, 0, 1) and Q represents the point (0, 1, 2).

Given, PQ = √27

From distance formula-

PQ =

⇒

Squaring both sides-

a² + 2 = 27

⇒ a² = 25

⇒ a = ±√25 = ±5

∴ a = 5 or a = -5

Option (A) and (B) both have one correct answer but only option (C) contains both the answers

Hence, option(C) is the most suitable choice.