Under which conditions will sugar most likely dissolve fastest in a cup of water? A. A sugar cube with stirring at 5°C
B. A sugar cube without stirring at 15°C
C. Sugar crystals with stirring at 15°C
D. Sugar crystals without stirring at 5°C

C) Sugar crystals with stirring at 15 degrees Celsius

Explanation:

Increasing surface area AKA, crystallizing a substance helps it reaction speed, other factors that help are increasing temperature and stirring.

i'm pretty sure its b i might be wrong though!