A Mass Spectral Analysis of 3-Methyl-1-Pentamine Showed a Base Peak $\left[\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}\right]^{+}$

A mass spectral analysis of 3-methyl-1-pentamine showed a base peak at m/z = 30. The base peak is because of _____.

A)
$\left[\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}\right]^{+}$
B)
$\left[\mathrm{H}_{3} \mathrm{C}-\mathrm{NH}_{2}\right]^{+}$
C)
$\left[\mathrm{H}_{2} \mathrm{C}=\mathrm{NH}_{2}\right]^{+}$
D)
$\left[\mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{3}\right]^{+}$