The two main parts of the nephron are: 

Concept: The capillaries and different tubules that make up the nephron's primary structure that aid in filtration and reabsorption. The structural and operational unit of the kidney is the nephron. 

Bowman's capsule is a cup-like structure at the beginning of the tubular component of a nephron. Renal tubules are long, fine, convoluted tubules which deliver urine from the glomeruli to the renal pelvis.

The glomerulus is a tuft of capillaries located inside the Bowman's capsule. Bowman's capsule and glomerulus are a part of the nephron.

The glomerulus along with the Bowman's capsule is called as the Malpighian body.

Hence, the correct answer is option A.