The correct order of increasing basicity of the given conjugate bases (R = CH₃) is

$RCO straight O with minus on top space less than space HC space identical to space straight C with minus on top space less than thin space straight N with minus on top straight H subscript 2 space less than straight R with minus on top$
$RCO straight O with minus on top space less than thin space HC space identical to straight C with minus on top space less than space thin space straight R with minus on top less than space straight N with minus on top straight H subscript 2$

$straight R with minus on top space less than HC space identical to space straight C with minus on top space less than space RCO straight O with minus on top space less than space straight N with minus on top straight H subscript 2$

$RCO straight O with minus on top space less than space straight N with minus on top straight H subscript 2 space less than HC space identical to straight C with minus on top space less than thin space straight R with minus on top$

Solution

RCO straight O with minus on top space less than space HC space identical to space straight C with minus on top space less than thin space straight N with minus on top straight H subscript 2 space less than straight R with minus on top

Stronger acid has a weaker conjugate base.
Order of acidity : RCOOH > CH≡CH > NH₃ > RH
Order of basicity : $RCO straight O with minus on top space less than space HC space identical to space straight C with minus on top space less than thin space straight N with minus on top straight H subscript 2 space less than straight R with minus on top$