Desperately need help.

1. Hydrologists want to analyze the volume of material carried by two rivers (expressed in grams of solid material per liter of water).One river drains a predominantly agricultural area, while the other river drains a predominantly forested area.Twelve random water samples are taken from each river.Which one of the following statistical techniques should they use to test whether differences in volume of material carried is significant ?A. Two sample difference of means.B.Multiple regression.C. Join-count analysis.D.One sample difference of means.Explain why this is the appropriate test.What is (are) the null hypothesis/hypotheses?