Answer:
The correct options are 1, 2 and 4.
Explanation:
The vertex form of an absolute function is

Where, (a,b) is the vertex of the function and x=a is axis of symmetry.
The function is symmetric with respect to the y-axis. It means the axis of symmetry is x=0. It is possible if the value of a in the vertex form is 0.
In option 1,

Here, a=0 and b=0.
Since the value of a=0, therefore it is symmetric with respect to the y-axis.
In option 2,

Here, a=0 and b=3.
Since the value of a=0, therefore it is symmetric with respect to the y-axis.
In option 3,

Here, a=-3 and b=0.
Since the value of a≠0, therefore it is not symmetric with respect to the y-axis.
In option 4,

Here, a=0 and b=6.
Since the value of a=0, therefore it is symmetric with respect to the y-axis.
In option 5,

Here, a=6 and b=0.
Since the value of a≠0, therefore it is not symmetric with respect to the y-axis.
In option 6,

Here, a=-3 and b=-6.
Since the value of a≠0, therefore it is not symmetric with respect to the y-axis.
Hence the correct options are 1, 2 and 4.