Memory Addressing - Alignment Clarification
Let's take a sample address, written in binary: 110100100110.

Now let's compute it modulo 2, 4, 8, 16, writing the answer in binary:


mod 2: 0
mod 4: 10
mod 8: 110
mod 16: 0110


(I recommend checking this.)

Hopefully you can connect the dots now.

As an additional hint, let's do a decimal example: 987348957943 mod 100 = 43. Why? Since the $i$th digit from the right (counting from 0) is "worth" $10^i$, so all the digits other than the two on the far right are "worth" some multiple of 100.