Measures of the Center of the Data · Exercise 12

We are interested in the number of years students in a particular elementary statistics class have lived in California. The information in the following table is from the entire section.
$$\begin{array}{cccc}\text{Number of years}& \text{Frequency}& \text{Number of years}& \text{Frequency}\\ \text{7}& \text{1}& \text{22}& \text{1}\\ \text{14}& \text{3}& \text{23}& \text{1}\\ \text{15}& \text{1}& \text{26}& \text{1}\\ \text{18}& \text{1}& \text{40}& \text{2}\\ \text{19}& \text{4}& \text{42}& \text{2}\\ \text{20}& \text{3}& & \\ & & & \text{Total = 20}\end{array}$$

What is the mode?

(a) 19
(b) 19.5
(c) 14 and 20
(d) 22.65

Its source prints no answer for this problem, so there's nothing to check against.

OpenStax, Introductory Statistics 2e · §2.5 Measures of the Center of the Data · Exercise 12