The question asks what the word lundi is. Lundi means Monday, and Monday is a jour de la semaine (day of the week).
The seven days of the week in French are: lundi (Monday), mardi (Tuesday), mercredi (Wednesday), jeudi (Thursday), vendredi (Friday), samedi (Saturday), and dimanche (Sunday).
The other options represent different categories of time or geography:
pays means country (e.g., la France, le Nigeria)
mois means month (e.g., janvier, fevrier)
saison means season (e.g., l'ete, l'hiver)
Note that in French, days of the week are not capitalised unless they begin a sentence.
