Your first option, silent deletion, will certainly not encourage the user and seems likely to send him away. The best you can hope for there is neutral -- he posts again, either because he's persistent or because he didn't notice the deletion. But either way, your action did not "result in a contributor that will be an ongoing asset to the site", so we can eliminate that one.
I base this on something Shog9 wrote on MSE:
A couple years ago now, we did some analysis of new user retention on Stack Overflow. Some forms of feedback tended to result in folks coming back more than others, but the single biggest way to keep someone away was to just ignore them. Don't vote - up or down. Don't comment. Don't answer. Don't close. Just... ignore. While you're busy walking on eggshells in fear of offending someone, they're seeing a blank page, an empty inbox, and they're walking away.
Granted that deletion is technically not ignoring, but silent deletion seems like the closest thing to ignoring other than just ignoring.
The Stack Overflow analysis suggests that, to help a new user learn your site, you need to respond in some way (either your second or third option). Shog continued -- I think this is now his opinion, not research results, but he's been a Stack Exchange CM for a long time so has been in a position to observe:
Here's how you guide new users: Lead by example, and treat them with respect. Even if you don't feel like it, even if you don't think they deserve it, even if they react badly to it anyway. If something needs editing, edit it. If something needs down-voting, down-vote it. If something needs critiquing, critique it. Patiently explain why. Answer questions, ask for feedback, stand your ground when you're right, and be willing to admit when you're wrong.
Now, not all users are ultimately going to work out. You can pour lots of effort into trying to teach somebody only to have him walk away, or jump in too much and become a drain. But I've seen users who started off on the wrong foot go on to be productive contributors to a site, and the key is that when you're looking at that first post, you don't know yet which type of user he is. So from a pragmatic standpoint, it's worth trying to help him out.
But this doesn't have to be time-consuming. You may see the same types of problems over and over, so develop some boilerplate comments, complete with links to the relevant resources on your site. You can then augment this text, if appropriate, with a bit about what the issue is in this specific post.
Finally, how much effort you "should" put into this depends on at least two factors: (a) how much does your site need new users (brand-new site, lots; SO, not so much) and (b) what is the opportunity cost of doing this guiding (what won't you be doing because you're doing this, and how important is that?). These considerations depend on your particular situation.
