Complications for telephone poll-takers include: a. the increase in the use of cell phones. b. the high costs of installing a landline. c. the use of answering machines. d. the lack of network coverage. e. the failure of landline connectivity.

The correct answer is letter A.

Explanation: Nowadays, cell phone use is becoming more and more common, and this results in some effects that are harmful to people, as well as physical causes such as telephone poll-takers, for example, who find it more difficult to perform their work.