The difference in mean size between shells taken from sheltered and exposed reefs was found to be 2 mm. A randomisation test with 10,000 randomisations found that the absolute difference between group means was greater than or equal to 2 mm in 490 of the randomisations. What can we conclude? Select one: a. There was a highly significant difference between groups (p = 0.0049). b. There was a significant difference between groups (p= 0.49). c. There was no significant difference between groups (p= 0.49). d. There is not enough information to draw a conclusion. Oe. There was a marginally significant difference between groups (p = 0.049).