$If|b|\ge 1$ and x = - |a| b, then which one of the following is necessarily true?

The correct option is C $a-xb\ge 0$
$|b|\ge 1\Rightarrow b\ge 1orb\le -1$
x = - |a| b (given)
Consider a - xb = a - (-|a|b)b
$=a+|a|b^2\ge 0$ since, $b^2\ge 1$

Quantitative Aptitude