How does this passage add tension to the play

This passage of Act V, Scene I, of "The Tragedy of Macbeth", by William Shakespeare, adds tension to the play because option C. The audience knows that Lady Macbeth is losing her mind and considering suicide before Macbeth knows this information. After Duncan's murder, Lady Macbeth starts losing her mind. In this passage she sees her bloodstained hands and she wants to clean them. She says that nobody can blame them because nobody knows what they have done.

the answer is a.

explanation:

the clause "looking toward the south" modifies "a funnel cloud." it's not really the cloud that's "looking," but grammatically, that clause is modifying the cloud.