Final answer:
Type 1 (distal) RTA occurs when the distal convoluted tubule fails to maintain the normal pH gradient between the tubular fluid and blood, leading to problems with blood pH and electrolyte balance.Thus the correct option is a.
Step-by-step explanation:
The type of Renal Tubular Acidosis (RTA) seen when the tubule loses the ability to maintain the usual pH difference between tubular fluid and blood is a) Type 1 (distal) RTA. In this condition, the distal convoluted tubule is unable to adequately secrete hydrogen ions, which leads to acid retention and therefore, a higher blood pH, known as metabolic alkalosis. A key function of the distal convoluted tubule is to selectively secrete and absorb different ions to maintain blood pH and electrolyte balance. The proximal convoluted tubule is mainly involved in reabsorption of ions, water, and nutrients, adjusting filtrate pH differently than the distal tubule. Therefore, an impairment in the distal tubule's function is directly associated with RTA Type 1.