No. 18 please help

 

Dear Student, DCT or distal convoluted tubules and cortical duct secrete potassium and hydrogen ions that maintains pH of blood and also helps to regulate sodium-Potassium balance of the body. This is performed via Sodium-potassium-hydrogen exchanger where sodium is reabsorbed in blood while potassium and hydrogen ions are secreted in urine. So, the answer is option (4). Regards