Not sure what precision level this problem is looking for, but for right-skewed distributions, we know that the mean is going to be pulled right and therefore the mean should be larger than the median. To a high confidence level, the mean should fall between 50 and 59, or in the third column.
If a single estimation is wanted, assume the values inside each column are uniformly distributed:
I think the correct answer from the choices listed above is option C. It is the metal Na that will react with water to produce a metal hydroxide and hydrogen gas. It reacts violently with water forming sodium hydroxide and the hydrogen gas.
