Capital gain taxation

Dear Sirs,

I am planning to sell a residential plot (land) in next 30 days, which I purchased in the year 2006 (Fy 2005-06). The net capital gain after indexation etc. works out to be Rs. 10 lacs. The options left before me are

A) pay capital gain tax as applicable and enjoy the balance

B) Invest the gain in a residential house purchase and avail tax benefit u/s 54F or so.

My question is if I already have a house can I avail option B.

Kindly advise.

Thanks in advance for your usual prompt responses

GR Babu