The Russians really have a quad (they also have mobile, truck mounted ICBM's that form a significant part of their deterrent, offering some of the guaranteed second-strike advantages that the US gets from SSBN's- and which their SSBN program does not provide nearly as well as the USN does). The Chinese only recently added a manned aircraft leg of their triad with the JL-1. The Indians technically have a triad- just no silo based systems, all of their land based missiles are from TELs, and they only have two SSBN's and do not do alternate crews so more than 1/3 of the time they don't have any deterrent at sea. The Israeli's are not believed to have any sea-based ballistic missiles, their sea-based deterrent would be Popeye cruise missiles and so vulnerable to interception. The Pakistanis are still building their first sea-based deterrent. The French and the UK have no land-based missiles, they are only sea-based and airplanes. The South Africans invested in the Jericho missile more for its space launched capabilities than its warhead delivery abilities, and never really looked at anything sea-based, so far as is publicly known.