Gone are the days where Manchester United used to have four top level strikers on the books, with a famous quartet fuelling the Treble in 1999. Changing tactics and a preference to play just one centre-forward at a time has reduced the number of strikers in squads, yet whichever way you look at it, Manchester United are light. The optimum number nowadays are probably two lead striking options and a top youth developmental prospect. Having a wide player who can fill in like Marcus Rashford, is just an added bonus. United only have Rasmus Hojlund and Anthony Martial. Except that Martial is never…