A $44-$kg student eats a $575-$Calorie $(575$ kcal$)$ jelly doughnut for breakfast.

$($a$)$

How many joules of energy are the equivalent of one jelly doughnut?

J

$($b$)$

How many stairs must the woman climb to perform an amount of mechanical work equivalent to the food energy in one jelly doughnut? Assume the height of a single stair is $15$ cm$.$

stairs

$($c$)$

If the human body is only $23\%$ efficient in converting chemical energy to mechanical energy, how many stairs must the woman climb to work off her breakfast?