The following question contains three sentences labelled as A, B, and C, each with a highlighted word. Identify the word from the given options that is the antonym of all three highlighted words.

A: The government tried to stymie the spread of misleading information through stringent regulations.

B: His antagonist employed various tactics to obstruct his progress at every turn.

C: They had to devise plans to hinder the flow of illegal goods across the border.