A function foo takes three integers as input arguments, i$.$e$.,$ foo$($int $a,$ int $b,$ int $c).$ The three inputs represent the three sides of a triangle in centimeter. The function is expected to

return the type of a triangle: "equilateral", "isosceles", or "scalene". Assume the domains of the three variables are $1a100,50b150$ and $100c200,$ respectively. A test

case is in a tuple format $S1S2S2-S1=S3,expecte{d}_o$utput$>$ with test inputs and the expected output.

$S1is$ a set $of$ test cases for the "Boundary Value Analysis" approach. $(0\mathrm{.}5pt)$

$S1=$

$S2is$ a set $of$ test cases for the "Robustness testing" approach. $(0\mathrm{.}5pt)$

$S2-S1=$

$S3is$ a set $of$ tests cases for the "Robust Worst$-$Case testing" approach. Are there any types $of$ triangles that $S3$ cannot reveal? $If$ yes, what are they? $Ifno,$ why? $(1pt)$