_________ I am afraid of dogs, my sister _________ lets her dog without a leash.

_ I am afraid of dogs, my sister _ lets her dog without a leash.

Since, never

Though, however

However, yet

None of these

"Though I am afraid of dogs, my sister, however lets her dog without a leash."

Explanation:

"Though"

is used to introduce a clause that is in contrast to the main clause.

"However"

is used to introduce an adverbial that contrasts the previous statement.