Unfortunately, the given options do not match the question prompt about "The Rainy Day". However, in response to the question, the speaker in "The Rainy Day" by Henry Wadsworth Longfellow expresses a melancholic and reflective mood regarding his youth. He seems to regret the lost opportunities of his youth and laments the passing of time. Therefore, option A, "He regards the past with longing and regret," best describes the speaker's attitude towards his youth in the poem.