Does the pH increase or decrease with each of the following additions? To what extent?

$($a$)5$ drops of $0\mathrm{.}1$MNaOH added to $100mL$ of $0\mathrm{.}5M$ acetate buffer:

decreases to a large extent

increases to a small extent

increases to a large extent

decreases to a small extent

$($b$)5$ drops of $0\mathrm{.}1MHCl$ added to $100mL$ of $0\mathrm{.}5M$ acetate buffer:

decreases to a small extent

decreases to a large extent

increases to a large extent

increases to a small extent

$($c$)5$ drops of $0\mathrm{.}1$MNaOH added to $100mL$ of $0\mathrm{.}5MHCl$ :

decreases to a large extent

increases to a small extent

increases to a large extent

decreases to a small extent

$($d$)5$ drops of $0\mathrm{.}1$MNaOH added to distilled water:

increases to a large extent

decreases to a small extent

decreases to a large extent

inereases to a small extent