Answer is: (4) proton and neutron.
One unified atomic mass unit is approximately the mass of one nucleon (proton or neutron).
The unified atomic mass unit (amu) is a standard unit of atom mass.
One unified atomic mass unit is approximately the mass of one nucleon (1.66·10⁻²⁷ kg).
For example, one carbon atom has mass of 12 amu (unified atomic mass).
The electron has a mass that is approximately 1/1836 that of the proton.

Actually Welcome to the Concept of the Ionic bonds.
Since Sodium (Na) is a cation and Chlorine (Cl) is a Anion, they both form a Ionic bond called as NaCl (common salt)
So answer is, Na and Cl
A) 4400 kj of heat released into surroundings
<h3>Further explanation</h3>
Reaction
C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O, the ∆H is –2200 kJ
Reaction exothermic( ∆H=-, released heat to surrounding) and for combustion of 1 mole of C3H8
So for two moles of C3H8, the enthalpy :
