Which is the correct sequence of labeling for the given figure?

• A
  $P$ - Valve,$Q$ - Ostia,$R$ - Pump,$S$ - Artery,$T$ - Haemocoel,$U$ - Artery
• B
  $P$ - Valve,$Q$ - Ostia,$R$ - Pump,$S$ - Artery,$T$ - Haemocoel,$U$ - Artery
• C
  $P$ - Valve,$Q$ - Ostia,$S$ - Artery,$T$ - Haemocoel,$R$ - Pump,$U$ - Vein
• D
  $P$ - Valve,$Q$ - Ostia,$S$ - Haemocoel,$T$ - Artery,$R$ - Vein,$U$ - Pump