If 0 < x < π and cos x + sin x <span class="math-tex">\(= \frac 1 2,\)</span> then the value of tan x is
(A) <span class="math-tex">\(\frac {-4 - \sqrt 7} 3\)</span>
(B) <span class="math-tex">\(\frac {4 + \sqrt 7} 3\)</span>
(C) <span class="math-tex">\(\frac {1 + \sqrt 7} 4\)</span>
(D) <span class="math-tex">\(\frac {1 - \sqrt 7} 4\)</span>