Choose A, B, C or D: What does the passage mainly discuss?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 28 to 34.

Some  animal  behaviorists  argue  that  certain  animals  can  remember  past  events,  anticipate  future ones,  make  plans  and  choices,  and  coordinate  activities  within  a  group.  These  scientists,  however,  are cautious about the extent to which animals can be credited with conscious processing.
Explanations of animal behavior that leave out any sort of consciousness at all and ascribe actions entirely  to  instinct  leave  many  questions  unanswered.  One  example  of  such  unexplained  behavior: Honeybees communicate the sources of nectar to one another by doing a dance in a figure-eight pattern. The orientation of the dance conveys the position of the food relative to the sun’s position in the sky, and the  speed  of  the  dance  tells  how  far  the  food  source  is  from  the  hive.  Most  researchers  assume  that  the ability  to  perform  and  encode  the  dance  is  innate  and  shows  no  special  intelligence.  But  in  one  study, when  experimenters  kept  changing  the  site  of  the  food  source,  each  time  moving  the  food  25  percent farther  from  the  previous  site,  foraging  honeybees  began  to  anticipate  where  the  food  source  would appear next. When the researchers arrived at the new location, they would find the bees circling the spot, waiting for their food. No one has yet explained how bees, whose brains weigh four ten-thousandths of an ounce, could have inferred the location of the new site.
Other  behaviors  that  may  indicate  some cognition  include  tool  use.  Many  animals, like  the  otter who  uses  a  stone  to  crack  mussel  shells,  are  capable  of  using  objects in  the  natural  environment  as rudimentary tools.  One  researcher  has  found  that  mother  chimpanzees  occasionally  show  their  young how  to  use  tools  to  open  hard  nuts.  In  one  study,  chimpanzees  compared  two  pairs  of  food  wells containing  chocolate  chips.  Allowed  to  choose  which  pair  they  wanted,  the chimpanzees  almost  always chose the  one with  the  higher  total,  showing  some  sort  of  summing  ability.  Other  chimpanzees  have learned to use numerals to label quantities of items and do simple sums.

What does the passage mainly discuss?

• A. The role of instinct in animal behavior.
• B. Observations that suggest consciousness in animal behavior.
• C. The use of food in studies of animal behavior. 
• D. Differences  between  the  behavior  of  animals  in  their  natural  environments  and  in  laboratory experiments.