I would say that D is the most important reason ie to monitor the location and magnitude of seismic activity to attempt to find patterns which may lead to the ability to predict the next earthquake in the world though individual seismic stations probably monitor more the seismic activity in their own country mostly though perhaps not exclusively.
Seismic data should be continuously monitored "to determine the location and magnitude of seismic activity".
<u>Explanation:</u>
Determining the location and magnitude is of utmost importance in order to analyze the patterns of activity so that this information can later be used to predict the earthquakes that could possibly happen in the future, and measures will be taken accordingly.
The smaller earthquakes provide enough information that helps seismologists to evaluate the distribution, frequency, and the hazards caused so that precautions could be taken for the same. All this information collected is extremely useful in creating building designs and land use planning decisions. Tsunami occurrences can also be monitored with the seismic data obtained.
