An agile team was performing very well till the fourth iteration. However, due to some unforeseen situations, it was not able to complete any story in the fifth iteration. How this situation will effect the burndown chart?
a. Slope of the burndown chart will become negative
b. Slope of the burndown chart will become zero
c. Slope of the burndown chart will become positive
d. Since the situation was unforeseen so fifth iteration would be cancelled