Which of the following is a characteristic of pernicious anemia?

Select the correct option regarding the circulatory system.

Assertion $A$: Anemia is sometimes observed in humans.
Reason $R$: There is a deficiency of iron and copper in the human body.
Which option is correct for Assertion $A$ and Reason $R$?

Statement-$I$: The first heart sound $(lub)$ is associated with the opening of the tricuspid and bicuspid valves.
Statement-$II$: Cardiac output of an athlete is much higher than that of an ordinary man.

Statement-$I$ :- The body has the ability to alter the stroke volume as well as heart rate and thereby the cardiac output.
Statement-$II$ :- During each cardiac cycle two prominent sounds are produced which can not be easily heard through a stethoscope.

Compare the statements $A$ and $B$.
$Statement A$: Blood sugar level falls rapidly after hepatectomy.
$Statement B$: The glycogen of the liver is the principle source of blood sugar.
Select the correct description: