Read the following passage and mark the letter A, B, C, or D to indicate the best option for each of the blanks.

Not everybody recognizes the benefits of new developments in communications technology. Indeed, some people fear that text messaging may actually be having a negative (15)_____ on young people's communication and language skills, especially when we hear that primary school children may be at (16)______ of becoming addicted to the habit. So widespread has texting become, however, that even pigeons have started doing it. What‘s more, in this case, it's difficult to view the results as anything but positive.

Twenty of the birds are about to (17) ______ to the skies with the task of measuring air pollution, each (18) _____ with sensor equipment and a mobile phone. The (19) _____ made by the sensors will be automatically (20) _____ into text messages and beamed to the Internet - where they will appear on a dedicated 'pigeon blog'.