If $f:[a, b] \rightarrow[c, d]$ is a continuous and strictly increasing function, then $\frac{d-c}{b-a}$ is

• A

  Value of the function at a point $t \in(a, b)$
• B

  Value of the function at $t \in(a, b)$ such that $f^{\prime}(t)=0$
• C

  Slope of the tangent drawn to the curve $y=f(t)$ at a point $t \in(c, d)$
• Correct answer
  D

  Slope of the tangent drawn to the curve $y=f(t)$ at a point $t \in(a, b)$

Hence, the correct answer is option: 'D'.