Which is the best revision of this sentence? teachers often have a hard time assigning boys who are generally more picky readers than girls, books to read. a) teachers often have a hard time assigning boys who are generally more picky readers than girls, books to read. b) teachers, often have a hard time assigning boys who are generally more picky readers than girls, books to read. c) teachers often have a hard time assigning boys, who are generally more picky readers than girls, books to read. d) teachers often have a hard time assigning, boys who are generally more picky readers than girls, books to read.