Must

As a general rule word "may" gave impression of its being enabling directory or discretionary power, while words "shall" and "must" gave impression of their being imperative, obligatory and mandatory but same were not tied up with hard and fast rule of being discretionary or imperative

Said words could be used interchangeably

Circumstances and fact of each case would determine interchangeability or convertability of words "may" for "shall" or "must" and vice versa

With change in circumstances, meanings and force of law also changed

Word "shall" under some circumstances, could not be treated and read as of mandatory connotation while same word from same law could be treated as of mandatory nature, if circumstances changed and requirement of time so warranted

Courts had to keep in view circumstances of each case while interpreting a word used in a legal instrument

Courts had not to be oblivious of ground realities.

S. 12 (a), (b) - Words "may" and "shall" used in cl. (a) & (b) of S. 12-Connotation-Held, punishing authority is empowered either to impose a fine without any limit and award sentence of imprisonment or in lieu of imposition of fine award sentence of imprisonment.-[Sentence].

"May", "must", "shall"-Interpretation-"May" in ordinary usage permissive and "must" imperative-Words "may" and "shall"-Interchangeable in legal phraseology depending on context in which used and not to be interpreted with rigidity attributed to them in ordinary parlance.-[Interpretation of statutes].