[单项选择]

Now which are the animals really to be pitied in captivity First, those clever beings whose lively urge for activity can find no outlet behind the bars of the cage. This is most conspicuous, even for the uninitiated, in the case of animals which, when living in a free state, are accustomed to roaming about widely. Owing to this frustrated desire, foxes and wolves housed, in many old-fashioned zoos, in cages which are far too small, are among the most pitiable of all caged animals.
Though pinioned swans generally seem happy, under proper care, by hatching and rearing their young without any trouble, at migration time things become different: they repeatedly swim to the lee side of the pond, in order to have the whole extent of its surface at their disposal, trying to take off. Again and again the grand preparations end in a pathetic flutter of their half wings ; a truly sorry picture !
This, however, rarely awakens the pity of the zoo visitor, least of all when suc
A. An opportunity for expression.
B. A place to let.
C. A chance of escape into a wood.
D. An exit for a marketer.