The name of the $H_2CO_3$ acid is and it is ?

$\begin{array}{1 1}(a)\;\text{Carbonic acid-strong acid}\\(b)\;\text{Carboneous acid-weak acid}\\(c)\;\text{Hydrocarbonic acid-strong acid}\\(d)\;\text{Carbonic acid-weak acid}\end{array}$

Carbonic acid
It is weak acid
Hence (d) is the correct answer.