How do I get the Z width of a specific xy Array position?

{
"c2array":true,
"size":[3,3,3],
"data":[
	[
		["Students"],
		["Simon"],
		["Sarah"]
	],[
		["Proben"],
		["Brüche zu Dezimalbrüchen 1","Mathe","Dezimalbrüche"],
		["Geometrische Flächen","Mathe","Geometrie"]
	],[
		["Themen"],
		["Dezimalbrüche","Mathe"],
		["Geometrie","Mathe"]
	]
]
}
[/code:2lualsp3]

How can i get the "depth" of i.e. "Geometrische Flächen"
or
how can i get the "height" of i.e. "Students" ?

Is there a possibility to do sth. like this: myArray.At(0).lengthor myArray.At(1,1).length.

Thank you