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.