I'm confused the the
best angle is is the greatest difference between power required and power available i.e highest ROC
and Vy is the greatest between
Thrust Horse Power required and
Thrust Horse Power available [slightly simplified]
where power is thrust * velocity so higher velocity means greater thrust horse power but and at Vimd you require the least thrust and least drag equating to the greatest spread of
Pr and Pa,...in the question it appears that at the greater velocity [124 kts] therefore the greatest difference in THPr and THPa i.e Vy
maybe the question meant Vx
