Which vascular component of the client's nephron delivers arterial blood from the glomerulus into the peritubular capillaries or the vasa recta?

The efferent (efferent means outgoing) arterioles are the blood vessels, which carry the blood away from the glomerulus. From the anastomotic capillaries into the cortex, which are also known as peritubular plexus the efferent arterioles bring the blood to the capillaries present in the medulla or vasa recta.

Hence, the correct answer is efferent arterioles.