If a2 + b2 + c2 = 1, then ab + bc + ac lies in the interval

GATE · 2015 · EC · Set 2 · General Aptitude

1. A.

   [1, 2/3]

2. B.

   [−1/2, 1]

3. C.

   [−1, 1/2]

4. D.

   [2, −4]