Hopefully I can help

First, let me just underline the relevant part to make it easier on the eyes.

The increase in the number and scope of investigations into monopolistic business practices, in addition to the expansion of definitions of such practices, have resulted in more antimonopoly litigation presently than ever before.

(A) have resulted in more antimonopoly litigation presently than ever before
(B) has resulted in greater antimonopoly litigation presently than previously
(C) has resulted in more antimonopoly litigation at present than was seen ever before
(D) have resulted in more antimonopoly litigation at present than ever before
(E) has resulted in more antimonopoly litigation at present than ever before


First off, this question is testing subject-verb agreement. Believe it or not but the subject is 'increase.' The GMAT is trying to trick you by throwing in a bunch of other information between the subject 'increase' and the verb 'to have.'

Because 'increase' is singular the verb needs to be 'has' not 'have.'

Just like that we've eliminated (A) and (D).

The next part of the underlined part that we want to focus on is 'than ever before.The use of 'previously' in (B) changes the meaning. 'Than ever before' implies there is more antimonopoly litigation than at any other time in the past. 'Previously' leaves open the interpretation that the number of litigation cases could have increased after initially going down. To illustrate:

1990: 500 litigation cases
2000: 300 litigation cases
2002: 350 litigation cases

Clearly 2002 is greater than previously (2000) but not greater than 1990.

So out with (B).

(C) is wordy, than was seen ever before


And just like that we have answer (E).

Hope that helped .

Thanks Chris, just one question.

Why is the subject only "The increase" and not a combined "The increase in the number and scope of investigations" which makes the verb plural.

Regards

Re-posting the question with underline,

The increase in the number and scope of investigations into monopolistic business practices, in addition to the expansion of definitions of such practices, have resulted in more antimonopoly litigation presently than ever before.

(A) have resulted in more antimonopoly litigation presently than ever before
(B) has resulted in greater antimonopoly litigation presently than previously
(C) has resulted in more antimonopoly litigation at present than was seen ever before - wordy
(D) have resulted in more antimonopoly litigation at present than ever before
(E) has resulted in more antimonopoly litigation at present than ever before

IMO: E