Decide Whether $\subset$ $\subseteq$ , Both, or Neither Can Be Placed in the Blank

Multiple Choice

Decide whether $\subset$ , $\subseteq$ , both, or neither can be placed in the blank to make a true statement.
- $\{ a , b \} \ldots \{ z , a , y , b , x , c \}$

A) Both $\subset$ and $\subseteq$
B) $\subseteq$
C) $\subset$
D) Neither