At Dot Com, a large retailer of popular books, demand is constant at $20,400$ books per year. The cost of placing an o to replenish stock is $$35,$ and the annual cost of hoiding is $$2\mathrm{.}00$ per book. Slock is received $12$ working days after a order has been placed. No backordering is allowed. Assume $275$ working days a year.

a$.$ Dot Com's optimal order quantity is books. $($Enter your response rounded to the nearest whole number$])$

b$.$ The optimal number of orders per year is $24$ arders. $($Enter your response rounded to the nearest whole number$)$

c$.$ The optimal interval $($in working days$)$ between arders is days. Enter your response rounjed to one decimal place,$)$

d$.$ The demand during lead time is books. $($Enter your response rounded to the nearest whole number.$]$