We know that there are 74 head, so we can just have 24 horses and 50 humans or 50 horses and 24 humans. Because 50+24=74
A is false, because 37+98≠74 and C too, because 31+74≠74.
So, it can be B or D.
If it's B, we have 24 horses and 50 humans. We have at all 196 legs.
And 24*4+50*2=196.
So it's, B, we have 24 horses and 50 humans.
(for D we have 24*2+50*4=248 or 248≠196)