Ms. usha
First af all understand the meaning of agricultural land. You are confused with the terms "agricultural land", "Urban area", and "rural area". The conditions provided by the central govt having regard to population and area are only for the purpose of differentiating between rural and urban land it does not have any link with the term agricultural land. If u see sec2 of the income tax act there u will see that any land used for agricultural purpose shall be agricultural land either it can be situated in rural area or urban area.
In ur case first of all see whether for the last two years (immediately preceeding the date of transfer) it is being used by ur parents for agriculture purpose, if yes it is a agricultural land and any capital gain arising on the sale of such land shall be exempt subject to the conditions prescribed u/s 54B. if not then it is not a agricultural land and it shall be subject to tax without any exemption. It does not matter whether it is situated in urban or rural area.