Final answer:
The Culebra Cut was dangerous due to the tropical heat potentially affecting dynamite stability, the risk of sparking deadly fires, and flying debris from the blasts killing workers, making 'All of the above' the correct answer.
Step-by-step explanation:
The Culebra Cut required a staggering 61 million pounds of dynamite, which posed extreme dangers due to several factors. To answer why it was dangerous, we must look at each option provided. Option (a), the tropical heat affecting the dynamite, is a possibility as heat can impact the stability of explosives. However, there are no specific incidents cited pertaining to this in the given context. Option (b), the dynamite sparking deadly fires, is a known danger associated with explosions, as seen in historical events where fires started by hot debris from an explosion caused significant destruction. This possibility is supported by precedents where explosions led to large-scale fires with catastrophic outcomes. Option (c), flying debris from the blasts killing workers, is a well-documented hazard of using explosives. Given the large-scale nature of the Culebra Cut, flying debris would have posed a significant threat to worker safety.
Therefore, the most comprehensive answer accounting for the dangers of using such a vast amount of dynamite in a project like the Culebra Cut would be (d) All of the above, as each factor contributes to the overall risk and has historical precedence.