which of the following has the largest de-Broglie wavelength (all have equal velocity)?

Atomic mass, NH₃​=17amu,CO₂​=44amu,
An electron is a tiny particle with a mass of 9.108×10−28 g and a negative charge. All neutral atoms contain electrons. The mass of a proton is 1.6726×10⁻²⁴ g, or about 1836 times the mass of an electron. The proton carries a positive electrical charge, that is equal in magnitude to the charge of the electron but opposite in sign. Mass of a neutron is 1.675×10⁻²⁴ g. It is very close to that of the proton. A neutron carries no charge.  therefore, electron  wavelength is maximum.$\mathrm{\lambda }\propto \frac{1}{\mathrm{m}}$