
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
Alice, Bob, and Carol went shopping and agreed to share the expenses equally. During their outing, Alice paid $120, Bob paid $150, and Carol paid $210. To balance their expenses equally, Alice gave Carol $a$ dollars, and Bob gave Carol $b$ dollars. What is $a-b$?
A) 20
B) 25
C) 30
D) 35
E) 40

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