Final answer:
The correct answer to which vessels supply the capillaries that interact with the nephrons is the afferent arterioles, which provide the initial blood input that will be processed by the nephron.
Step-by-step explanation:
The capillaries supplying individual nephrons with blood are part of an intricate system within the kidneys. These capillaries are initially fed by the afferent arterioles. The afferent arterioles branch off into the glomerular capillaries that form the glomerulus, a tuft of high-pressure capillaries crucial for filtering the blood based on particle size. After this first phase of filtration in the glomerulus, the blood exits via the efferent arterioles, which lead to a secondary capillary network. This network includes the peritubular capillaries surrounding the renal tubule and the vasa recta in juxtamedullary nephrons, both of which play essential roles in reabsorbing substances back into the blood. As such, The capillaries supplying individual nephrons are fed by the afferent arterioles, which are the initial source of blood for the glomerulus and subsequent peritubular capillary network.