I have been solving some exercises on Maximum Likelihood estimation and I got across this one-
It is known that the proportion of smokers (p) in a population lies in the interval $[1/3, 2/3]$. In a random sample of N individuals selected from the population, it was found that M were smokers. The maximum likelihood estimate of p based on the above data is
(A) $max\left\{1/3, M/N\right\}$
(B) $min\left\{M/N, 2/3\right\}$
(C) $M/N$
(D) none of the above.
I am completely new to this kind of problem where an interval for the parameter is given. My approach is to take MLE as $M/N$ if $M/N$ lies in the given interval, but it does not match with any of the options. I don't know what to take MLE if $M/N$ lies outside of the interval. Please tell me how to proceed in this kind of situation.