请教：大全-5-20

20.   For a local government to outlaw all strikes by its workers is a costly mistake, because all its labor disputes must then be settled by binding arbitration, without any negotiated public-sector labor settlements guiding the arbitrators. Strikes should be outlawed only for categories of public-sector workers for whose services no acceptable substitute exists.

The statements above best support which of the following conclusions?

(A) Where public-service workers are permitted to strike, contract negotiations with those workers are typically settled without a strike.

(B) Where strikes by all categories of pubic-sector workers are outlawed, no acceptable substitutes for the services provided by any of those workers are available.

(C) Binding arbitration tends to be more advantageous for public-service workers where it is the only available means of settling labor disputes with such workers.

(D) Most categories of public-sector workers have no counterparts in the private sector.（C）

(E) A strike by workers in a local government is unlikely to be settled without help from an arbitrator.

这道题在说的什么呀？我怎么一点出摸不着头脑。