The Ten-Year-Old Child Was Diagnosed with a Medulloblastoma; Following Surgery

The ten-year-old child was diagnosed with a medulloblastoma; following surgery the child is started on chemotherapy by intrathecal injection. While preparing the family for the start of chemotherapy, the nurse will explain that intrathecal administration was chosen because:

A) It reduces side effects.
B) It does not require the child being "stuck."
C) Many chemotherapy drugs do not cross the blood-brain barrier.
D) Intrathecal administration is less expensive than intravenous administration.