B) if they mean 'three decades' literally, then she was with him right after the verdict or maybe even before.
True, but the article also says she was with Marvin from 1965 to 1970, he cut her off financially in late 1971, and she filed suit in Feb of 1972. So it wasn't like she went straight from Marvin's company to Van Dyke's.
Btw, I find it a little funny that, despite saying "If a man wants to leave his toothbrush at my house, he better bloody well marry me," she was Van Dyke's companion, not wife, for nearly 30 years. So something changed her mind, although it obviously was worth it as she and Van Dyke had a fairly lengthy relationship.