Go against the tide means to oppose the usual opinion, trend, or direction. The correct answer is this meaning because the expression is used figuratively, not only by its literal words.

Examples:

• The scientist was brave enough to go against the tide.
• In an HSC essay, Go against the tide can express this meaning: to oppose the usual opinion, trend, or direction.
• When this expression appears in a passage, connect Go against the tide with the idea of to oppose the usual opinion, trend, or direction.