organic help (which is correct and why?)

Cyclic chain is the main chain, while others are acting as being substituted. If the alkyl chain would have been longer, the cyclic chain was to be considered as substitued

Can you take the cyclic chain as a substituent no right...... so 2nd one isn't the answer!

oh yeah thanks Vivek! I feel lazy studying IUPAC nomenclature so just I forgot somethings!

I was wondering can we name by the second way... is it possible we can have part of ring as substituent!

No, Part of ring cannot be named. If 2 or more rings are together then they are named according to as IUPAC rules for Bicyclo or Spiro compounds.