One third of a number, z, added to one fifth of the same number is 3/5 . What is the number and why?

A) 40/3 , because the equation that represents this sentence is 3z+5z=3/5 .

B) 6/5 , because the equation that represents this sentence is 1/3z+1/5=3/5 .

C) 3/40 , because the equation that represents this sentence is 3z+5z=3/5 .

D) 9/8 , because the equation that represents this sentence is 1/3z+1/5z=3/5 .

PLEASE HELP ANSWER THX!!! :)