Final answer:
The true statement regarding manufacturing cycle efficiency (MCE) is that if the value added time and the throughput time both decrease, then the MCE will always increase, as long as the decrease in value added time does not outpace the decrease in throughput time. Correct option is (a).
Step-by-step explanation:
The question is asking which statement is true regarding the impact on manufacturing cycle efficiency (MCE) when there are changes in value added time and throughput time. The manufacturing cycle efficiency (MCE) is calculated as the value added time divided by the throughput time.
Statement a suggests that if the value added time decreases and the throughput time also decreases, MCE will always increase. This statement is true, because MCE is a ratio of value added time to throughput time; if both decrease proportionally, the ratio will increase, assuming the decrease in value added time does not outpace the decrease in throughput time.
The other statements (b, c, d) have scenarios where either both value added time and throughput time increase, or value added time decreases while throughput time increases, or value added time increases while throughput time decreases, which do not necessarily result in an increase in MCE.