[单选题]
One 20-year-old twin brother takes a space0b)m l 6lmabfa8+jn)w trip with fs le72t+ snzoj;,7ira speed of 0.80c for 30 years according to a coes2j fi ,+l7nrt s7;zlock on the spaceship. Upon returning to the Earth, what is his own age and the age of the Earth-based twin brother?
