This permits a value to be inserted for every competitor, for every event entered. The disadvantage is that the field has a different "meaning" depending on the context. In some cases it will be a distance in other cases it will be a time. This is a serious problem, however this answer is the best of a poor set of options.
This will not work as only one value can be stored per event - we should record a value for every competitor for every event.
This only permits one value to be stored per competitor. Some polyathletes are entered in more than one event.
This will work - but only if there are exactly three events. The design of the database is geared to permitting a variable number of events. This is a very serious problem - a "less bad" solution is listed.
This is not a good solution. It would permit each competitor to enter no more than two events.
An athletics meeting involves several competitors who participate in a number of events. The database is intended to record who is to take part in which event and to record the outcome of each event. As results become available the winner attribute will be updated with the cid of the appropriate competitor.
Competitor(cid, name, nationality) Event(eid, description, winner) Competes(cid, eid)
The database is to be modified. A time in seconds is to be recorded for each runner, a distance in metres is to be entered for each jumper and for each thrower. Select the most appropriate modification: