The surprise tactic failed because one of the party planners let out the secret.
D. Possessive.
Howard's apostrophe means that it is his, therefore possesive.
It is also called a dative case..represented by <em>dat or d</em> ..it indicates that noun to whom something is given..like <em>she gave Jess a book..</em> here Jess is dat or prepositional case..
