An investor purchases $$25,000$ in mutual fund units on January $1$st$.$ On April $1$st$,$ he receives $$580$ in dividends and reinvests them in additional units. On July $1$st$,$ he purchases an additional $$5,000$ in units. As of September $1$st$,$ he holds a total of $2,200$ units. If he redeems $1,000$ units at a price of $$32$ on September $2$nd$,$ and assuming no other transactions have occurred, what is the book $($cost$)$ value of the remaining units?

Question $3$ options:

$$13,900$

$$16,680$

$$22,935$

$$32,580$