Who drinks blood in the woods?

The correct answer is Abigail Williams, as she is the character who directly engages in the act of drinking blood in the woods. This pivotal scene occurs when Abigail, along with her group of friends, participates in a ritual to invoke the spirits in an attempt to curse Elizabeth Proctor. The act of drinking blood symbolizes both the desperation of the group and their willingness to engage in dark magic to achieve their desires. Abigail's motivations stem largely from her obsession with John Proctor and her desperation to remove Elizabeth from the picture, which in turn leads to the subsequent hysteria and tragic events of the Salem witch trials.

In contrast, Mary Warren, Betty Parris, and Tituba, while central to the narrative, do not drink blood in this context. Mary Warren is involved in the trials but is not the one to initiate such a dark act. Betty Parris has her own struggles and is affected by the chaos but does not partake in the blood-drinking ritual. Tituba, although she is a key figure in the witchcraft accusations and is initially accused of conjuring spirits, does not drink blood in the woods in the manner described in the question. Thus, Abigail Williams is the focal point of this specific act, making her the correct answer.