Consider an arbitrage-free one-period market model. Which of the following statements hold? Select one or more: a. The set of replicable securities form a vector space (i.e the sum of two replicable securities is replicable and every scalar multiple of a replicable security is itself replicable) of dimension at most d + 1. b. There exists a replicable security. C. Every security is replicable. d. If C is replicable, then there exists a unique replicating portfolio