A dislocation line in a fcc crystal dissociates into two partials which have their Burger vectors as $$\frac{a}{6}\left[ {2\overline 1 \overline 1 } \right]$$  and $$\frac{a}{6}\left[ {11\overline 2 } \right],$$  Indicate the correct statement.

A. Burgers vector of the undissociated dislocation line is $$\frac{a}{2}\left[ {10\overline 1 } \right]$$

B. Burgers vector of the undissociated dislocation line is $$\frac{a}{2}\left[ {1\overline 1 0} \right]$$

C. Energy of each partial is proportional to $$\frac{{{a^2}}}{3}$$

D. Energy of the undissociated dislocation line is lesser than the sum of energy of two partials

Answer: Option A