A Nurse, Assisting a Physician with the Insertion of a Central

A nurse, assisting a physician with the insertion of a central venous catheter, instructs a client to perform the Valsalva maneuver during the insertion of the catheter. The purpose of instructing the client to perform the Valsalva maneuver is to:

A) make PICC insertion easier.
B) prevent thrombus formation.
C) prevent air from entering the circulation.
D) prevent malposition of the catheter during insertion.