$7+6+5+4+3+2+1=28$ 
There were $$8$$ students in a class. Each student shook hands only once with the other $$7$$ students in the class. How many handshakes were there in total? 
Options:
a. $$28$$ 
b. $$36$$ 
c. $$49$$ 
d. $$56$$ 