Identify the true statements and choose the correct option accordingly.
$I.$ Blood vessel leading to the glomerulus is called efferent arteriole.
$II.$ Vasa-recta,peritubular capillaries and glomerulus,all have blood.
$III.$ Cortical nephrons have highly reduced vasa-recta.
$IV.$ Vasa-recta runs parallel to the Henle's loop in the juxta-medullary nephron.

• A
  $I, II$ and $III$
• B
  $I, II$ and $IV$
• C
  $I, III$ and $IV$
• D
  $II, III$ and $IV$