Banana Masturbation? What do you think these texts means?

A woman is texting with her boyfriend about different stuff and eventually the bf texts something like "So I saw your girlfriend yesterday". Gf texts something like "Who?" Bf "Your friend Gladys." Gf "Oh yeah?" Bf "Yeah, but bad news, she's cheating on you, saw her with a guy, lol, guess you'll have to stick with guys...or bananas " Gf "Lol I guess so". So then he texts about where he saw her and other stuff. As the conversation starts to end the gf texts "Oh, and please don't tell anyone about the banana :$" Bf replies, "don't worry, I won't."

So based upon those texts, what do you think is the most likely story behind the banana comment?

A. During a sexual encounter between the boyfriend and girlfriend, a banana was used, maybe he used it on her or she let him watch her use it on herself.

B. The girlfriend told her boyfriend about a bisexual encounter she had with Gladys or another woman in which the other female used a banana on her.

C. The girlfriend told her boyfriend about how she has masturbated in the past with a banana.

D. Another explanation.

Please answer which one you think is the likely story and provide detailed reason why you think it is most likely. If you want, you can even explain why you think one or more reasons are not likely.