求教一个逻辑问题 急!!

In 1981, for the first time in over two decades, the average scores of high school students on standardized math and English tests did not decline. During the same year, millions of American students enjoyed their first exposure to the new world of the microcomputer, whether in schools, video arcades, or other settings. The conclusion is clear: far from stultifying the intellectual capacities of students, exposure to computers can actually enhance them.

The most serious weakness of the argument above is its failure to

(A) discuss the underlying causes of the twenty-year decline in students’ test scores

(B) cite specific figures documenting the increases in test scores

(C) distinguish among the various types of computer being used by high school students

(D) define the intellectual capacities tested by the standardized math and English tests referred to

(E) explain exactly how high school students’ abilities on math and English tests could have been enhanced by exposure to computers

答案是E是有道理的,可是D错在哪里呢?  我觉得数学和英语的标准测试并不一定代表智力测试啊,两个概念不同的有必要解释说明的