The statement $F \subset D$ means that set $F$ is a subset of set $D$. A set $F$ is a subset of another set $D$ if all elements of $F$ are also elements of $D$.

Let's check this:

• Set $F = \{r, s\}$
• Set $D = \{p, r, s, t\}$

Now, look at the elements of $F$:

• Element $r$ is in $D$.
• Element $s$ is in $D$.

Since all elements of $F$ are in $D$, we can conclude that:

$F \subset D$

Therefore, the statement $F \subset D$ is true.

Would you like any further details or have any questions?

Here are 5 related questions to explore:

1. What is the difference between a subset and a proper subset?
2. Can a set be a subset of itself?
3. What does $F \subseteq D$ mean, and how is it different from $F \subset D$?
4. Is the empty set a subset of all sets?
5. If $G = \{s\}$, is $G \subset F$?

Tip: A set is always a subset of itself, but it is only a proper subset if it doesn't contain all elements of the other set.