The solidity of bridge piers built on pilings depends largely on how deep the pilings are driven. Prior to 1700, pilings were driven to "refusal, " that is, to the point at which they refused to go any deeper. In a 1588 inquiry into the solidity of piers for Venice' s Rialto Bridge, it was determined that the bridge' s builder, Antonio Da Ponte, had met the contemporary standard for refusal: he had caused the pilings to be driven until additional penetration into the ground was no greater than two inches after twenty-four hammer blows. Which one of the following can properly be inferred from the passage? ['After 1588, no bridges were built on pilings that were driven to the point of refusal.', "Da Ponte's standard of refusal was less strict than that of other bridge builders of his day.", 'The Rialto Bridge was built on unsafe pilings.', 'It is possible that the pilings of the Rialto Bridge could have been driven deeper even after the standard of refusal had been met.']