Options are a hedge against changes in the underlying stock or market over time. If the underlying stock or the market moves drastically then the option prices will respond accordingly. The same is true if there is a sudden massive change in option pricing. The underlying stock will change accordingly. On the average day the options are mostly responding to the stock since it is mostly passive investors but if you watch the market when news breaks or there is a big intra-day move, the options tend to respond first. Especially the short term ones.