Scientists have determined the average salinity of ocean water to be equal to a. 3.45 g/ml b. 34.5 g/kg c. 34.5 g/ml d. 3.45 g/kg

 b. 34.5 g/kg

The average salinity of the ocean would be 3.45% or 35 parts per millions(ppm). That means 3.45% of the ocean water weight would be contributed by salt. Water density is 1kg/liter or 1000g/1000ml.
Then, 3.45% of it would be: 3.45% * 1000= 34.5g/kg or 34.5g/l

The metal is named first