$S$ 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.

• A
  $a$
• B
  $b$
• C
  $c$
• D
  $d$