Which of the following pair of nuclides are Isobars?

${}_1^2H,{}_1^3H$ ${}_1^3H,{}_1^2H$ ${}_{80}^{198}Hg,{}_{79}^{197}Au$ ${}_1^1H,{}_1^3H$

${}_1^3H,{}_1^2H$

The correct answer is Option (2) → ${}_1^3H,{}_1^2H$