. A cup of coffee cools from \(90^{\circ} \mathrm{C}\) to \(80^{\circ} \mathrm{C}\) in t minutes, when the room temperature is \(20^{\circ} \mathrm{C}\). The time taken by a similar cup of coffee to cool from \(80^{\circ} \mathrm{C}\) to \(60^{\circ} \mathrm{C}\) at a room temperature same at \(20^{\circ} \mathrm{C}\) is:
A \(\frac{13}{10} t\)
(B) \(\frac{13}{5} t\)
(c) \(\frac{10}{13} t\)
D \(\frac{5}{13} t\)
