Areader who wants to determine whether a book contains specific information would look in the
a. table of contents.
b. index.
c. publishing information.
d. synopsis.

the answer is subjective. i personally agree with the first answer for this question.

if one isn't strictly talking about objects then the correct answer would be 'my eyes' since according to this riddle i am asleep and in order to answer/open the door i need to open my eyes first of all.

however, if one is specifically looking for an object, then the first thing i would open would be the door

hope this !