Which sentence is capitalized correctly?

only one solution is possible: we must cut our expenses.

only one solution is possible: we must cut our expenses.

only one solution is possible: we must cut our expenses.

only one solution is possible: we must cut our expenses.

Read this excerpt from the scarlet letter by nathaniel hawthorne and complete the sentence that follows. she had wandered, without rule or guidance, in a moral wilderness; as vast, as intricate and shadowy, as the untamed forest, amid the gloom of which they were now holding a colloquy that was to decide their fate. the author uses the point of view in the excerpt.