What is the PH of a solution which turns a red litmus blue? <br>A) 2 B) 6 C) 8 D) 10

Question

$\begin{array}{1 1} (a)\; A,B \;and\;D \\ (b)\;C\;and\;D \\ (c)\; B \;and\;D \\ (d)\; \text{All of theses} \end{array} $