The fraction of the volume of a glass flask must be filled with mercury ,so that the volume of the empty space may be the same at all temperatures is (reads α= 9x10-6/°C, γHg = 18.9x10-5/°C)

1) 1/2
2) 1/7
3) 1/4
4) 1/5

I have a test tomorrow

So, please answer it for me and please don't spam otherwise I will report it and also give proper step by step explanation since I have test

Will mark BRAINLIEST if correct answer is given to me

Expecting answers from high ranked users​