Inattentional Blindness occurs when:

a) sensory systems become more sensitive when using attentional resources.
b) sensory systems become less sensitive when using attentional resources.
c) failure to notice something that is completely visible because of a lack of attention .
d) sensory systems become less sensitive to a stimulus as it changes.
e) none of the above

Inattentional Blindness occurs when (d) sensory systems become less sensitive to a stimulus as it changes.

Explanation:

Inattentional Blindness refers to the cause of the indifferent behavior of each individual without paying attention to the act of normal actions. Such a course of action is linked with cognitive psychology.  Cognitive form of psychology helps to sharpen the knowledge of mindful thought when human society applies it in the particular action of daily incidents. When the lack of such cognitive effects failed to concentrate on certain action operations also leads to Inattentional Blindness.

For example, When one individual fails to recollect the subject knowledge when he attempts to write an exam for a particular subject. Here his attention fails and his effort of passing the exam also gets fails. It is due to the cause of less mental sharpness. At last, this also paves the way for less sensitive to a stimulas condition. Stimulas is nothing but the influencing factor of making so attentive in his every operative action.

the density would be a smaller number.