I just got a book voucher for a moderately
sizeable amount (actually a rather large amount if only spent on paperback
books). As they’d put it on an SAT test, Brian is to internet bookshops as kid is to ______.

I just got a book voucher for a moderately
sizeable amount (actually a rather large amount if only spent on paperback
books). As they’d put it on an SAT test, Brian is to internet bookshops as kid is to ______.