(A) Document is a singular noun and takes the third person singular form of the verb to be: is.
Choice (B) is the first person singular form.
Choices (C) and (D) are plural forms.

     (A) success

     (B) succeed

     (C) successful

     (D) succession

(C) This is the adjective form, used to describe the noun businessperson.
Choices (A) and (D) are nouns.
Choice (B) is a verb.

You will find all the pencils you need _____ that drawer.

     (A) through

     (B) under

     (C) on

     (D) in

(D) The pencils are inside, or in, the drawer.
Choice (A) describes movement from one side to another.
Choice (b) and (C) are extremely unlikely places to find a pencil relative to a drawer.

Several important pieces of information were _____ from the report.

     (A) omit

     (B) omitted

     (C) omitting

     (D) omission

(B) This is a passive voice sentence and uses the past participle form of the verb.
Choice (A) is the simple present or base form.
Choice (C) is the present participle.
Choice (D) is the noun form.

If the weather is bad, we _____ the trip

     (A) will cancel

     (B) have canceled

     (C) canceled

     (D) are canceling

(A) A future real conditional sentence uses future tense in the main clause.
Choice (B) is present perfect.
Choice (C) is simple past.
Choice (D) is present progressive.