男性，45岁，进行性消瘦，贫血、乏力、右下腹扪及包块，大便隐血试验阳性。最可能的诊断是（）

A.降结肠癌

B.结肠息肉

C.溃疡性结肠炎

D.升结肠癌

E.慢性细菌性痢疾

The following questions present a sentence, part of which or all of which is underlined. Beneath the sentence, you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is best, choose the first answer; otherwise choose one of the others.

These questions test correctness and effectiveness of expression. In choosing your answer, follow the requirements of standard written English; that is, pay attention to grammar, choice of words, and sentence construction. Choose the answer that produces the most effective sentence; this answer should be clear and exact, without awkwardness, ambiguity, redundancy, or grammatical error.

The stock market collapse of 1929 had far-reaching consequences for the national economy, causing a nationwide collapse in home values, putting millions out of work, and by erasing the investment savings of one-fifth of the population.（）

A. and by erasing

B. and erasing

C. and having erased

D. and erased

E. by erasing