Scientists predict that several effects can occur due to solar flares, including:
a. Electrical systems in satellites will fail - True. Solar flares can interfere with the electronics on satellites, potentially causing malfunctions or failures.
b. High-frequency radio waves used for radio communication will be blocked - True. Solar flares can cause ionospheric disturbances, affecting high-frequency radio communication.
c. Radio navigation systems and global positioning systems will be inaccurate - True. Solar flares can disrupt the ionosphere, leading to inaccuracies in radio navigation and GPS systems.
d. Power grid operations will go offline - True. Severe solar flares can induce geomagnetic storms that may lead to disturbances in power grid operations and, in extreme cases, outages.
In summary, all the listed options (a, b, c, and d) are potential effects of solar flares.