Which of the following is true of copyrights? Select one O a. A copyright begins when the work is fixed in tangible form, for example, when a book is written O b. Copyright law protects original ideas in tangible or intangible form O c. They Copyright Act is limited to forms of expression that can be written on paper and preserved O d. A copyright in the U.S. lasts for the life of the author or fifty years, whichever is shorter O e. The Berne Convention mandated the use of the copyright symbol in order to establish copyright