When cell has stalled DNA replication fork, which checkpoint should be predominantly activated?

If DNA replication fork is stalled, then G₂/M checkpoint is activated to prevent progress into M stage.
(1) G1/S checkpoint is activated if environmental conditions, such as very low temperature, inadequate supply of nutrients etc., are not favourable.
(3) M checkpoint or spindle assembly checkpoint is activated if any chromosome is not attached to spindle
fibre.
(4) Only G2/M checkpoint is activated but not spindle assembly checkpoint of M stage.