In a certain province in France there are 17 cities. If a single road segment connects only two cities, how many road segments are required in order to connect the cities so that each city is connected to all other cities with a single road segment?
Choose the correct choice from the following answers
A) 30	B) 105	C) 330	D) 136	E) 156
1 city needs 16 roads to connect directly to the rest =&gt; 17 city needs 17*14 roads.   One road is counted twice =&gt; the number of road needed is 17*16/2= 
<gadget id="calculator">17*16/2</gadget>
<output>136</output>
136   Answer 136
<result>D</result>
In a certain province in France there are 17 cities. If a single road segment connects only two cities, how many road segments are required in order to connect the cities so that each city is connected to all other cities with a single road segment?