Final answer:
In 'Grettir's Saga,' the monster fights predominantly occur during winter, with one significant fight, the battle with the draugr Glámr, happening around the winter solstice. Option 4.
Step-by-step explanation:
In Grettir's Saga, a classic of Icelandic literature, the monster fights take place during winter. The saga mentions several battles against supernatural forces that occur in this season.
For example, Grettir's famous battle with the draugr, Glámr, takes place around Yule, the winter solstice. As the days get shorter and colder, the darkness and harsh weather conditions contribute to the atmosphere and setting for these chilling encounters.
So Option 4.