The correct answer is option 2: if frost occurs during the period of ripening. Frost can negatively impact the sucrose content in sugarcane because it damages the plant cells and disrupts the process of sugar accumulation. When sugarcane is exposed to frost, the cells can burst and cause the breakdown of sucrose stored in the plant. This leads to a decrease in sucrose content. It is important for sugarcane to undergo a proper ripening process in order to accumulate high levels of sucrose. Frost during this crucial period can hinder the ripening process and result in lower sucrose content. Therefore, frost can have a negative impact on the quality of sugarcane and ultimately affect the sugar yield.