Double
Explanation:
Since the period T of a pendulum is given by

By increasing the length of the pendulum by 4, the period becomes

You can see that the period doubles when we increase the length by a factor of 4.
The circuit component the symbol represents is: C) Battery
According to my research I found questions with the same info with option choices and they are:
A.) How many people in the study had the flu?
B.) How many people were included in the study?
C.) What was the average age of the people in the study?
D.) What was the most common occupation of people in the study?
Among those options the answer would be the second choice B)