Andy's Father Moved to the United States 12 Years Ago

Andy's father moved to the United States 12 years ago. When he moved to the United States from Italy with his mother eight years ago, Andy was six and his sister was thirteen. Who among the following is likely to have the least strength of accent while learning the non-native language (English) ?

A) His mother because women usually fare better than men and children in learning new languages without accent.
B) Andy because childhood is a better time to speak a second language without an accent.
C) His father because the length of time has a bearing on the strength of one's accent.
D) His sister because adolescence is a better time to learn and be proficient in a second language without an accent.