To solve this problem, we need to analyze the given statements:$\newline$Assertion (A): Nephrons are of two types: Cortical \& Juxta medullary, based on their relative position in cortex and medulla.$\newline$Reason (R): Juxta medullary nephrons have short loop of Henle whereas, cortical nephrons have longer loop of Henle.$\newline$Let's break down each statement:$\newline \bullet$Assertion (A):$\newline$ - Nephrons are indeed classified into two types based on their location: cortical nephrons and juxtamedullary nephrons.$\newline$ - Cortical nephrons are located primarily in the renal cortex, while juxtamedullary nephrons are located near the junction of the cortex and medulla.$\newline$ - Therefore, Assertion (A) is correct.$\newline \bullet$Reason (R):$\newline$ - Juxtamedullary nephrons actually have a long loop of Henle that extends deep into the medulla.$\newline$ - Cortical nephrons have a shorter loop of Henle.$\newline$ - Therefore, Reason (R) is incorrect.$\newline$Now, let's determine the relationship between (A) and (R):$\newline \bullet$While Assertion (A) is true, Reason (R) is false.$\newline$Therefore, the most appropriate answer is Option 3: A is true but R is false.