Task: Pos Tagging
Input (English): Sentence: Rather , such assignments are made , as they must be , on the {{ basis }} of certain overall rules and standards , representing to some extent a statistical approach to the problem , taking into account for each situation some of the variables ( e.g. , power and station separations ) and averaging out others in order to achieve the balance which must be struck between protection against destructive interference and the assignment of a number of stations large enough to afford optimum radio service to the Nation . 
Word: basis
Output (English): NOUN