Is it okay to submit article to Journal B despite contacting editors of Journals A & C?
I see no reason to delay. Editors are busy and sometimes take a while to respond, but that shouldn't block the author as long as you don't submit to multiple places simultaneously. Of course, if it has been less than a week or so, the editor might be a bit grumpy. 

However, consider which journal would be the best fit for the paper. This will help you determine whether it is worth it to you to delay. 

Note that any response from an editor wouldn't be a commitment to publish, but only encouragement to do so. You would still be free at that point in any case.