
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
There were five teams entered in a competition. Each team consisted of either only boys or only girls. The number of team members was $9, 15, 17, 19$, and $21$. After one team of girls had been knocked out of the competition, the number of girls still competing was three times the number of boys. How many girls were in the team that was eliminated?
A) 9
B) 15
C) 17
D) 19
E) 21

Present the answer in LaTex format: \boxed{Your answer}
user