Answer: B. It is venous but extends to the right brachiocephalic vein. The central line is inadvertantly deep and likely resulted from the guidewire being displaced by the patient's PICC line. This patient will need the line removed/replaced.

Estimated Central Line Lengths for Correct Placement:
Right Internal Jugular Vein: 13 cm, +/- 2 cm
Right Subclavian Vein: 15 cm, +/- 2 cm
Left Internal Jugular Vein: 15 cm, +/- 2 cm
Left Subclavian Vein: 17 cm, +/- 2 cm

References:
1. McNeil C, Rezaie SR, Adams BD: Central Venous Catherization and Central Venous Pressure Monitoring, in Roberts JR, Hedges JR, Custalow CB, et al (eds): Clinical Procedures in Emergency Medicine, ed 6. Philadelphia, Saunders, 2013, Ch 22:p 397-434.
2. LITFL: Central Venous Catheters