Sentence Correction

The normative model of strategic decision-making suggests that executives examine a firm's external environment and internal conditions, and in using the set of objective criteria they derive from these analyses, can decide on a strategy.

[spoiler]A. conditions, and in using the set of objective criteria they derive from these analyses, can decide
B. conditions, and they use the set of objective criteria derived from these analyses in deciding
C. conditions and, in using the set of objective criteria derived from these analyses, deciding
[/spoiler]
D. conditions and, using the set of objective criteria derived from these analyses, decide
E. conditions and, in their use of the set of objective criteria they derive from these analyses, they decide


Can expert explain me what is the subject of the above sentence correction?

If find two nouns 1. Normative model 2. Executives.
Why Model can't be the subject of the sentence?

the modifier (using the set .... as shown in answer choice D ) must modify the subject executives and the verb examine.
But I got confused with the word 'model' ,this can be a subject. If it is not a subject please state your reason.