What cannot be obtained through research on plants in a botanical garden?

What is the importance of a Herbarium?

Where are plant,animal,and fossil specimens collected,preserved,and stored for study and reference?

Assertion $(S)$: Rare genes can be preserved in botanical gardens.
Reason $(R)$: Gene banks are developed in botanical gardens.
$(A)$ Both $S$ and $R$ are true,and $R$ is the correct explanation of $S$.
$(B)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(C)$ $S$ is true and $R$ is false.
$(D)$ $S$ is false and $R$ is true.

$S$ Statement: Periodic poisoning is done to protect against fungi,insects,and moisture.
$R$ Reason: To preserve dried plant specimens,they are sprayed with specific chemicals; this process is called poisoning.
$(a)$ Both $S$ and $R$ are true,and $R$ is the correct explanation of $S$.
$(b)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(c)$ $S$ is true and $R$ is false.
$(d)$ $S$ is false and $R$ is true.

How does a botanical garden differ from a herbarium?