Fill in the blank: The wide exposure and immediate access to the source code of open-source tools makes it ______ likely that issues will occur.

The correct answer is B. less.

Explanation: The phrase suggests that because the source code of open-source tools is widely available, it allows many developers to inspect, test, and improve the code. This collaborative scrutiny tends to reduce the likelihood of issues occurring, making problems less likely in open-source software compared to closed-source alternatives.