The values of dissociation constants $(K_a)$ of some acids (at $25\,^{\circ}C$) are as follows. Indicate which is the strongest acid in water:
$(A)$ $1.4 \times 10^{-2}$
$(B)$ $1.6 \times 10^{-4}$
$(C)$ $4.4 \times 10^{-10}$
$(D)$ $4.3 \times 10^{-7}$

• A
  $1.4 \times 10^{-2}$
• B
  $1.6 \times 10^{-4}$
• C
  $4.4 \times 10^{-10}$
• D
  $4.3 \times 10^{-7}$