A hedger has bought two Australian dollar $($AUD$)$ futures contracts at the closing price on day $t=0.$ Over the subsequent days, the futures price has evolved as shown in the following table.

All values are the closing futures price for that day.

Each futures contract on the Australian dollar has a size of AUD$125,000,$ an initial margin of CHF$2,000,$ and a maintenance margin of CHF$1,300.$ In addition, the hedger never withdraws any

excess funds from the margin account and always meets any required margin calls.

What is the balance of the margin account at the end of $t=4?$

a$.CHF1,750$

b$.CHF3,500$

c$.CHF3,212\mathrm{.}50$

d$.CHF6,425$