Option B is the correct answer.
When sugar is exposed to heat, the first thing to occur is that the sugar melts into a thick syrup.
When sugar is put on a heat, and it reaches a temperature of 320 degree F or 160 degree C, the sugar starts to melt. The solid crystals of sugar begin to melt at this temperature. Sugar crystals join together to form a thick caramelized syrup. After more heating, it will change the color to light brown.