Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
                    "explanation": "EXPLAIN WHY THE ANSWER IS CORRECT"

            ]

            Text:
            ber.
In response to mild occlusal stimulus, secondary
dentin is mainly deposited in the pulp horns and
on the roof and floor of the pulp chamber so
after many decades the chamber becomes quite
narrow occluso-gingivally.
2. Secondary Dentin
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This constriction in pulp chamber size reduced the
possibility of pulp exposure in old patients during
cavity or crown preparation.
The dentist must pay attention for the size and
location of the pulp chamber to decide the design
of the preparation and placement of retentive
features such as pins.
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Sclerotic Dentin
(Transparent or Peritubular dentin)
This type of dentin results from aging or mild
irritation (such as slow caries, attrition, abrasion,
erosion and occlusal trauma) and causes a change in
the composition of the primary dentin.
The tubular content appears to be replaced by
calcified
material
that
obliterates
the
tubules,
progressing from the DEJ pulpaly.
The tubules become progressively hypermineralized
and, with constriction of the lumen and less
permeable. The sclerotic dentin is harder, denser,
less sensitive and more protective of the pulp
against subsequent irritation.
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Sclerosis resulting from aging is (physiological dentin
sclerosis) and that resulting from mild irritation
called (reactive dentine sclerosis).
The combination of peritubular wall thickness and
intratubular
crystals
creates
a
zone
of
hypermineralized dentin beneath exposed or carious
dentin, the zone of sclerosis or translucent zone.
Sclerotic dentin is frequently found beneath both
active caries lesions and restorations and is an
important defense reaction of the hard tissues
because it limits the permeability of dentin.
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Reparative dentin (tertiary dentin)
Intense traumatic insult (injury) to the tooth, whether
caused by bacterial penetration associated with
caries, or heat and trauma from a dental bur, may be
severe enough to destroy the supporting odontoblasts
in the affected location. Within 3 weeks, fibroblasts or
mesenchymal cells of the pulp are converted or
differentiated to simulate the activities of original
odontoblast, and form irregularly organized atubular
dentin called reparative dentin.
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Tertiary
Secondary 
Primary 
Dentin formed before root 
completion
Formed after root 
completion
Formed as a response to any external 
stimuli such as dental caries, attrition 
and trauma
Usually formed by primary 
odontoblasts
Found in all areas of dentin
Regular
Rapid
More
Formed by primary 
odontoblasts
It is not uniform, mainly 
present over roof and floor 
of pulp chamber
Irregular
Less
Secondary odontoblasts or 
undiferentiated mesenchymal cells 
of pulps
Localized to only area of external 
stimulus
Atubular
Rapid between 1.5 and 35 um/day 
depending on the stimuli
Least
Definition
Type of cells
Location
Orientation of 
tubules
Rate of formation
Slow
Permeability
Thank You 
For Your Attention 
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