Which of the following is a valid mathematical statement?

The maximum tension a rope can withstand is $60 ~kg-wt$. The ratio of maximum acceleration with which two boys of masses $20 ~kg$ and $30 ~kg$ can climb up the rope at the same time is

The correct order of increasing ionic character is:

Below are two statements. One is labeled as Assertion $(A)$ and the other as Reason $(R).$
Assertion $(A):$ Gypsum is used to make boards for fireproof walls.
Reason $(R):$ Gypsum is unstable at high temperatures.
In the context of the above statements,choose the correct answer from the options given below:

The formula of the product formed when sodium thiosulphate solution is added to silver bromide is:

Which of the following national parks is the home of the famous musk deer or Hangul?