Diaphragms are contraceptive devices used by females. Choose the correct option from the statements given below:
$i$. They are introduced into the uterus
$ii$. They are placed to cover the cervical region
$iii$. They act as physical barriers for sperm entry
$iv$. They act as spermicidal agents

• A
  $i$ and $ii$
• B
  $i$ and $iii$
• C
  $ii$ and $iii$
• D
  $iii$ and $iv$