Sentence Correction

The territory historically inhabited by the Kurdish people (includes portions of ) Turkey, Iran, Iraq, Syria, Armenia, and Azerbaijan.
includes portions of
include
included portions of
included a portion of
including

My answer was d because i chose to go with the past tense.However correct answer is A.What is the technique?

src_saurav wrote:The territory historically inhabited by the Kurdish people (includes portions of ) Turkey, Iran, Iraq, Syria, Armenia, and Azerbaijan.
includes portions of
include
included portions of
included a portion of
including

My answer was d because i chose to go with the past tense.However correct answer is A.What is the technique?

A. includes portions of
B. include . Wrong- verb does not agree with singular suject territory
C. included portions of
D. included a portion of . Wrong. a portion is used for 1 place where a list of countries were mentioned.
E. including . Wrong. The territory including Turkey... is not a sentence.

A and C are possible answers.