听力原文： Over the past decade, the environmental movement has exploded onto the minds of mainstream consumers, a fact not lost on marketers and advertisers. Green advertising started in the mid-1980s when issues of the environment muscled their way to the forefront of marketing. Advertisers saw the consumer desire for environmentally safe products and tried to meet the demand as quickly as possible. Not surprisingly, this first wave suffered from rough and poorly conceived marketing efforts. Many advertisers embraced a genuine concern for the environment. But consumers realized that some companies made false claims and exploited the movement, using such ambiguous terms as "environmentally friendly" and "green". Consumers grew wary of environmental appeals, and advertisers reacted by reducing its emphasis. In 1992 the Federal Trade Commission established guidelines for green marketing, followed shortly by state governments. California passed particularly strict laws, setting definitions for terms like "ozone friendly", "biodegradable", and "recycled". According to the state's court, "California seeks to guard against potentially inaccurate claims or ecological boost about products with minimal environmental attributes." Texas, Massachusetts, Minnesota, Tennessee, Connecticut, and Washington soon followed the Golden State's lead. The rigid regulations have left a number of advertisers confused and frustrated, although some feel that environmental claims have already peaked and are on their way out. Some believe that we've now entered green advertising's third wave, during which environmental concern is part of the mainstream, too.
(33)

A. They were expensive.
B. No one believes them.
C. They were unsuccessful.
D. They were often deceptive.