If <span class="math-tex">\(\vec a,\; \vec b\)</span> and <span class="math-tex">\(\vec c\)</span> are the position vectors of the vertices A, B, C of a triangle ABC, then the area of the triangle ABC is
(A) <span class="math-tex">\(\frac 1 2 |\vec a \times \vec b + \vec b \times \vec c + \vec c \times \vec a|\)</span>
(B) <span class="math-tex">\(|\vec a \times \vec b|\)</span>
(C) <span class="math-tex">\(\frac 1 2 |\vec a \times \vec b - \vec b \times \vec c \times -\vec c \times \vec a|\)</span>
(D) <span class="math-tex">\(|\vec a \times (\vec b \times \vec c)|\)</span>