@sohail420 ... Welcome to Webmasterworld!

Me, #1 would be my choice. Why? Makes more sense as a webmaster. After all, I'm the one who has to maintain the beast. :)

Are you looking at this from an ecommerce point of view?

Hi sohail420 and welcome to WebmasterWorld [webmasterworld.com]

Because your question contains the standard taxonomy of a WordPress site (/category/ /page/ /post/) I am guessing that the question is about the optimal permalink syntax/structure? Understanding that WP content is shown in numerous ways, the thing to keep in mind is to create your syntax based on the content. If your content already has existed in one URL syntax or another your indexing could take a hit while google crawls and indexes the "new" content, especially if you have been using a canonical link meta tag to point to the page you would prefer to be indexed.

Is the change worth the trouble? Look at your sitemaps, the URLs that you have been submitting to Google for indexing. Do you see the same content on different URLs? Make sure that you select the format you want to have indexed and add canonical meta tags to all other URLs that lead to the same content. This helps you avoid competing against yourself.

When others link to your content using different URLs and you are submitting all of them to Google, you leave it for them to decide which URL to index and if there is no canonical tag they see all those URLs as duplicate content.. You can see why it is important to have a plan before starting but once it exists, plan your use of meta canonicals to create order.

Yoast explains this concept clearly: [yoast.com...]