Answer B option.
To get maximum number of Reduce moves, we should make sure than in each sentential form only one terminal is reduced. Since there is no unit production, so last 2 tokens will take only 1 move.
So To Reduce input string of n tokens, first Reduce n-2 tokens using n-2 reduce moves and then Reduce last 2 tokens using production which has . So total of n-2+1 = n-1 Reduce moves.
Example for this could be :
S-->aA
A-->bB
B-->cC
C->de
Generate string of 5 tokens as
S-->aA
-->abB
-->abcC
-->abcde
So first we take 3 steps to reduce ' abc ' and then take 1 step to produce ' de '. So total (5-2) + 1 = 4 Reduction moves