The largest functional value of the function $\mathrm{f: y = \frac{x+1}{x}}$ on the interval $[1, 2]$ is:
$(A)$ $1$
$(B)$ $3/2$
$(C)$ $2$
$(D)$ The function f does not have a maximum on the interval $[1, 2]$.
Why is $x = 2$ the correct answer instead of $x = 1$, given that when $x = 2$, the result is $1.5$, when $x = 1$, the result is $2$, and when $x = \frac32$, the result is $1.66$?