Removal of the proximal convoluted tubule (PCT) from the nephron will result in more concentrated urine.

The PCT is responsible for the reabsorption of most of the water, glucose, amino acids, and ions (such as sodium, chloride, and bicarbonate) that are filtered out of the blood by the glomerulus. This reabsorption occurs through active and passive transport mechanisms, which help maintain the proper balance of ions and water in the body.

If the PCT is removed from the nephron, less water and solutes would be reabsorbed, and more would be excreted in the urine. This would lead to a higher concentration of solutes in the remaining tubules and collecting ducts, and ultimately to the production of more concentrated urine.

So, option D, "more concentrated urine," is the correct answer.