A community can provide for its water storage needs using either a high level elevated steel tank A or a low level tank B on a nearby hill. Tank A will cost $$150,000$ and tank B $$120,000.$ Annual operating, maintenance and repair costs will be $$6,000$ for tank A and $$10,000$ for tank B$.$ Using the annual cost method with $6\%$ interest rate, determine which option will be preferable assuming a $50$ year lifespan of the project:

$($a$)$ When there is no salvage value

$($b$)$ When there is a salvage value of $5\%$ at the end of $50$ years.