Select the most appropriate option to fill in the blank.

Officials said thousands of office-goers were ____________the Metro, and the trains were running full during peak hours.

taking

The most appropriate option to fill in the blank is taking.

The sentence is about office-goers taking the Metro to work. The word "taking" is the most appropriate word to use because it accurately describes the action of riding the Metro.

The other options are not as appropriate.

• Fasting means abstaining from food and drink. It does not make sense in this context, because office-goers are not abstaining from food and drink.
• Running means moving quickly. It does not make sense in this context, because the trains are not running quickly.
• Adapting means changing to fit new conditions. It does not make sense in this context, because the office-goers are not changing to fit new conditions.