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.
- $\{ s , r , t \} \ldots \{ s , r , t \}$

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