Selected data points of the step response of a stable first-order linear time-invariant (LTI) system are given below. The closest value of the time constant (in seconds) of the system is:
\[
\begin{array}{|c|c|}
\hline
\textbf{Time (sec)} & \textbf{Output} \\
\hline
0.6 & 0.78 \\
1.6 & 2.8 \\
2.6 & 2.98 \\
10 & 3 \\
\infty & 3 \\
\hline
\end{array}
\]