Final answer:
For every student who votes for the planetarium, two students vote for the zoo. The ratio of planetarium voters to zoo voters is 1 to 2. The number of votes for the planetarium is half the number of votes for the zoo.
Step-by-step explanation:
A. For every student who votes for the planetarium, two students vote for the zoo.
B. The ratio of planetarium voters to zoo voters is 1 to 2.
C. The number of votes for the planetarium is half the number of votes for the zoo.