MathematicsHard202×since 2002Q5804If a→, b→,\overrightarrow a ,\,\,\overrightarrow b ,a,b, and C→\overrightarrow CC are unit vectors such that a→+2b→+2c→=0→,\overrightarrow a + 2\overrightarrow b + 2\overrightarrow c = \overrightarrow 0 ,a+2b+2c=0, then ∣a→×c→∣\left| {\overrightarrow a \times \overrightarrow c } \right|a×c is equal to :A154{{\sqrt {15} } \over 4}415B14{{1} \over {4}}41C1516{{15} \over {16}}1615D1516{{\sqrt {15} } \over 16}1615Check answerSkip