For an acid-base indicator,the dissociation constant $K_a = 1.0 \times 10^{-5}$. The indicator is red in acidic form and blue in basic form. What is the $pH$ range required for the color change from $80\%$ red to $80\%$ blue?

• A
  $4.4$
• B
  $5.6$
• C
  $1.2$
• D
  $3.8$