In the Manusmriti which form of marriage results from the “Voluntary union of a maiden and her lover”?

According to the Manusmriti, the 'voluntary union of a maiden and her lover' is defined as the Gandharva form of marriage. The Manusmriti (Chapter III, Verse 21) lists eight specific forms of marriage rites in a sequential order: Brahma, Daiva, Arsha, Prajapatya, Asura, Gandharva, Rakshasa, and Paishacha. In this traditional enumeration, the Gandharva form is explicitly identified as the sixth form. This union arises from mutual desire and sexual intimacy between the couple rather than parental arrangement. While the first four forms (Brahma, Daiva, Arsha, and Prajapatya) are generally considered approved or 'Prashasta', the Gandharva form belongs to the latter four, which were often viewed with varying degrees of social or religious caution depending on the caste, though it was recognized for its basis in love.