I'd need more information as to your overall credit picture to offer an actual conclusion to answer your question. However, based only from what you posted aka credit steps is for a new card - and given your low limit of $300, I'll assume you are either new to credit cards or have some credit "issues" on your reports. Capital One is not generally going to issue you a second card when the first one is still on "probation".
You can only be approved for 1 card every 6 months. AFAIK the limit is 5 cards
1 Personal Card and 1 Business Card in a 6 month period, and yes 5 is the limit.
ADDITIONAL DISCLOSURES & TERMS AND CONDITIONS
Pulled directly from Capital One's terms and conditions.