as the chief cargo door engineer for a major aircraft manufacturer, you are responsible for redesigning the door to prevent further accidents. in order to install the new cargo doors as soon as possible, you are considering redesigning the door before knowing the official results of the accident investigation team. you know that the possible causes of failure are reduced to either a malfunction of the latch, or a malfunction of the electric actuators that close the door. you estimate that there is a 70% chance that bolt failure will be identified as the cause of the accident and a 30% chance that the motors will be to blame. the four options you are considering are (a) the bolt is now redesigned at a cost of $30,000; (b) engine redesign now at a cost of $25,000. (c) both are now redesigned, at a cost of $35,000. and (d) awaiting the results of the accident investigation before deciding which component to redesign. if you choose either (a) or (b) and a component you did not redesign is determined to be the cause of the failure, it will cost you an additional $25,000 for a quick redesign of the bolt and an additional $45,000 for a quick redesign of the actuator. also, if you choose (d), your design costs are tied into an accelerated schedule. which option has the lowest expected cost?