Final answer:
The deal between Lord Berterak and Sir Gawain is not accurately represented in the options provided and does not directly correspond to the known Arthurian tales where Sir Gawain makes a pact with Lord Bertilak.
Step-by-step explanation:
The deal between Lord Berterak and Sir Gawain is a legendary exchange from the tales of the Knights of the Round Table, particularly those recounted in the Arthurian legends. This question seems to have some variation in character name as the traditional literature speaks of Sir Gawain and Lord Bertilak, not Berterak.
The correct answer to the provided options, however, appears not to be directly related to the well-known tale of Sir Gawain and the Green Knight, where Gawain enters into a pact with Lord Bertilak (also known as the Green Knight) to exchange whatever gains they have earned over three days.
ince the exact reference in the question does not align with the traditional stories of Sir Gawain, answering based on the details provided in the options rather than the traditional story, none of the provided answers (magical sword, sharing wealth, sparing life, or hosting for a feast) correspond directly to the known tales involving Sir Gawain.