Fill in the Blanks: Archaeologists believe that the pieces of red-ware pottery excavated recently near Bhavnagar and ______ shed light on a hitherto dark 600-year period in the Harappan history of Gujarat.

A

estimated with a reasonable certainty as being about 3400 years old,

B

are estimated reasonably certain to be about 3400 years old,

C

estimated at about 3400 years old with reasonable certainty,

D

estimated with reasonable certainty to be about 3400 years old,