Inbound anchor text - which one should i use?

Keyword 1 only or keyword 1, keyword 2..ect

[itravelvietnam]

Dear all,
I am just wondering which option I should use in anchor text on inbound links:

Option 1:

Only one keyword per backlink

for example "Keyword 1" for inbound link 1
and "Keyword 2" for inbound link 2

Option 2:

Multiple keywords per inbound link

for example "keyword 1, keyword 2, keyword 3...ect" for all backlinks.

Please advise.

Thank you very much for your reply.

Kurt