The correct options are
A The unit of rate constant for a zero order reaction is mole litre−1sec−1.
B Half life of a first order reaction is inversely proportional to rate constant.
C For zero order reaction rate constant is equal to the rate of reaction at all concentrations.
D For a first order reaction , the rate constant (k) is related to half life (t12) as k=0.693t12
For 1st order reaction t12=0.693k
For zero order reaction rate k[A]0
Therefore all of the above are correct statements.