Which of the following is/are correct?

• A

  ${\mathrm{P}}^{\mathrm{H}}=-\log \left[{\mathrm{H}}^{+}\right]$

• B

  ${\mathrm{P}}^{{\mathrm{K}}_{\mathrm{a}}}=-\log {\mathrm{K}}_{\mathrm{a}}$

• C

  ${\mathrm{P}}^{{\mathrm{K}}_{\mathrm{b}}}=—\log {\mathrm{K}}_{\mathrm{b}}$

• D

  All of these