Answer:
A). The reason you're reading.
Step-by-step explanation:
Reading is a comprehensive activity that requires the interest of the readers and to build or develop the interest, one must have a reason to read that justifies that 'why are you reading a particular text?" For example, some people read books for knowledge while some read for mere entertainment.
Thus, the purpose of reading reflects the reason for reading and that eventually decides the method and style of reading. A purpose or reason is something that keeps the interest and curiosity intact and motivates the readers to read more. It also assists to enhance the effectiveness of reading. Thus, option A is the correct answer.