What was the outcome of Canfrancesco della Scala's attempt to resist the Visconti of Milan in 1387?

A. He negotiated a peace treaty with the Visconti and remained in Verona
B. His efforts failed, and he joined his father in exile in Ravenna
C. He was captured by the Visconti and imprisoned
D. He successfully defended Verona and forced the Visconti to retreat
Answer: 