In a safety stock problem where both demand and lead time are variable, demand averages 150 units per day with a daily standard deviation of 16, and lead time averages 5 days with a standard deviation of 1 day. What is the standard deviation of demand during lead time?
A) 15 units
B) 100 units
C) 154 units
D) 500 units
E) 13,125 units
Answer: C