<span>Assuming that this is referring to the same list of options that was posted before with this question, <span>the correct response would be that "iron rails were easily replaceable", since in fact that represented relatively permanent infrastructure. </span></span>
What are the possible answers to fill the blank?
Answer:
Soldiers are marching in a parade. There are 10 soldiers in a row. What is the rule which gives the number of soldiers, given the number of rows?