Which of the following statements is correct?

• A
  In cortical nephrons,the loop of Henle is too short and extends only very little into the medulla.
• B
  In juxtamedullary nephrons,the loop of Henle is too short and runs deep into the medulla.
• C
  In cortical nephrons,the loop of Henle is very long and extends only very little into the medulla.
• D
  In juxtamedullary nephrons,the loop of Henle is very long and extends only very little into the medulla.