Rutherford's initial atomic model, though crucial for understanding the nucleus, didn't explicitly include neutrons. Rutherford's model, developed in 1911, identified a small, positively charged nucleus at the atom's center, but it only included positively charged protons within this nucleus. The neutral neutron was discovered later, by James Chadwick, in 1932. 

Rutherford's experiment involved bombarding a thin layer of gold with alpha particles (helium nuclei). The results showed that most alpha particles passed through the gold foil with little deflection and a small fraction of alpha particles were deflected at large angles.

Rutherford's observations led him to propose the nuclear model of the atom, which states that:

1. Atoms have a small, dense, positively charged nucleus (containing most of the atom's mass).

2. The nucleus is surrounded by a cloud of electrons.

The deflection of alpha particles in Rutherford's experiment was indeed caused by the massive, positively charged nucleus. The nucleus's positive charge and concentrated mass led to the scattering of alpha particles at large angles. The nucleus is not described as "very large" in Rutherford's theory. Instead, it's the empty space surrounding the nucleus that's large, allowing most alpha particles to pass through with minimal deflection.

These also make option D incorrect, leaving us with option A and D as the answers, although more likely option D.