How to get rejected

No time for blogging today (it's a 12 hour day packed into 6), so I'll leave you with a question that's been plaguing me since my 20s. You're a guy who is interested in a gal. You ask her out. Would you rather that she (a) fobs you off with a line about being busy, without providing an alternative date; or (b) says something along the lines of "I'm incredibly flattered that you'd ask me out but I'd rather not." Both are rejections, but they take very different forms. One is implied, one direct. Which is preferable?