$[-/4$ Points$]$

SCALCET$82\mathrm{.}1\mathrm{.}002.$

A cardiac monitor is used to measure the heart rate of a patient after surgery. It compiles the number of heartbeats after $t$ minutes. When the data in the table are graphed, the slope of the tangent line represents the heart rate in beats per minute.

$\backslash$table$[[t(min),36,38,40,42,44],[$Heartbeats$,2540,2682,2816,2955,3088]]$

The monitor estimates this value by calculating the slope of a secant line. Use the data to estimate the patient's heart rate after $42$ minutes using the secant line between the points with the given values of $t.($Round your answers to one decimal place.$)$

$($a$)t=36$ and $t=42$

$($b$)t=38$ and $t=42$

$($c$)t=40$ and $t=42$

$($d$)t=42$ and $t=44$