What is likely the issue if there is dial tone on one phone but not on two others connected to different outlets?

The correct choice, which identifies the likely issue as an open circuit or break in conductor, is valid given the situation described. When there is a dial tone present on one phone but not on two others connected to different outlets, it suggests that there may be a disruption in the wiring or connections that affect those specific outlets.

In a typical telephone line setup, if one device can receive a dial tone while others cannot, this often indicates that the problem lies within the wiring or connections leading to the non-functional phones. An open circuit signifies a break in the conductor line, preventing electrical signals necessary for the dial tone from reaching those outlets.

While a defective power source could indeed affect telephone operation, it is less likely in this scenario because the operational phone is successfully receiving a dial tone. A mismatch in telephone technology can also be ruled out, as the functioning phone indicates that there is compatible technology present on the line; if it were a compatibility issue, none of the phones would be able to receive a dial tone. Lastly, an issue with the telephone service provider would typically affect all connected devices uniformly rather than selectively impairing some while others work fine. Therefore, the presence of a dial tone on one phone strongly points to a localized wiring issue, validating the selection