which of these would be supported by the graph?

C. KBr is about twice as soluble as NaCl at 60°C

Explanation:

From the graph of solubility of various solutes with respect to temperature we can figure-out that on y-axis we have the increasing solubility of the solvents in gram per 100 gram of water as we move upwards and on x-axis we have increasing temperature of the solvent (water) moving rightwards.

As we move vertically up through 60°C line we notice that NaCl has solubility nearly 40 grams per 100 gram of water whereas on further moving up in the same line we find that KBr has nearly 80 gram per 100 gram of solubility.

The solubility of NaCl varies negligibly with change in the temperature of water whereas the solubility of KNO3 is greatly increased by the increasing temperature.

it would be c. predictability