Answer: B
$\log_{10}x – log_{10}\sqrt{x} = 2 \log_x10$
$\implies log_{10} \frac{x}{\sqrt{x}} = \frac{2}{\log_{10}x}$
$\implies \log_{10}\sqrt{x} = \frac{2}{\log_{10}x}$
$\implies \frac{1}{2}\log_{10}x = \frac{2}{\log_{10}x}$
$\implies (log_{10}x)^2 = 4$
$\implies \log_{10}x = \pm 2$
$\implies x = 100 \text{ or } \frac{1}{100}$