You are designing a spell generator for a hypothetical game. Each spell can have a theme (e.g., ice, lightning, insects), a cost (e.g., craft items, player stats), and a benefit (e.g., attack, healing, persuasion). According to Zubek, players will be most interested if:

A. You broaden the action space by highly differentiating costs and benefits

B. You give freedom to choose the benefit they like, holding theme and cost steady

C. You give freedom to choose the cost they like, holding benefit and theme steady

D. You give freedom to choose the theme they like, holding cost and benefit steady

E. You make spells memorable by highly differentiating costs or benefits