The correct option is (c) secretion.
Explanation:
Mechanism of uric acid excretion in a nephron is secretion. As blood passes through the kidneys, the nephrons clear the plasma of some substances (e,g. urea/uric acid) while simultaneously retaining other, essential substances (water). Substances to be excreted are removed by glomerular filtration and renal fubular secretion and passed into the urine. Secretion refers to the transport of solutes from the peritubular capillaries to the tubular lumens.
