Several factors (steric,electronic,orbital interactions,etc.) can affect the inversion barrier of an amine. In the given pairs,which data is correctly placed?

• A
  Comparison of $N(CH_3)_3$ and $N(i-Pr)_2(CH_3)$ with $\Delta G^{\ddagger} = 7.9 \ kcal/mol$ and $0.2 \ kcal/mol$ respectively.
• B
  Comparison of $N$-methylaziridine and $N$-methylpyrrolidine with $\Delta G^{\ddagger} = 20.5 \ kcal/mol$ and $7.0 \ kcal/mol$ respectively.
• C
  Comparison of $N(CH_3)_3$ and $NCl_3$ with $\Delta G^{\ddagger} = 7.9 \ kcal/mol$ and $22.9 \ kcal/mol$ respectively.
• D
  All of these