Read the paragraph from an essay about conservation.
Many companies claim to be ‘green,’ but few are practicing true conservation of resources. Though e-mails have replaced paper memos, lights use LED bulbs, and toilets are a modern ‘low-flow’ variety, waste is rampant. Trash cans overflow with recyclables. Outlets hum with the recharging of personal electronic devices, and office parking lots boast a shameful number of gas-guzzling trucks that are piloted morning and night by lone commuters too self-absorbed to consider a carpool.
How does the author's word choice affect the tone of the paragraph?

The words green and conservation impart a concerned tone.
The words resources and recyclables impart an academic tone.
The words shameful and self-absorbed impart a critical tone.
The words personal and lone impart a confidential tone.