In the reading room of a library, there are 23 reading spots. Each reading spot consists of a round table with 9 chairs placed around it. There are some readers such that in each occupied reading spot there are different numbers of readers. If in all there are 36 readers, how many reading spots do not have even a single reader?	Choose the correct choice from the following options:
A) 8
B) 16
C) 15
D) 14
E) 9
1+2+3+4+5+6+7+8= 
<gadget id="calculator">1+2+3+4+5+6+7+8</gadget>
<output>36</output>
36   so, 8 spots are occupied by users    23-8= 
<gadget id="calculator"> 23-8</gadget>
<output>15</output>
15,   ANSWER:15
<result>C</result>
In the reading room of a library, there are 23 reading spots. Each reading spot consists of a round table with 9 chairs placed around it. There are some readers such that in each occupied reading spot there are different numbers of readers. If in all there are 36 readers, how many reading spots do not have even a single reader?