Kconfig

 1choice
 2	prompt "This is always invisible"
 3	depends on n
 4
 5config DUMMY
 6	bool "DUMMY"
 7
 8endchoice
 9
10choice
11	prompt "Choose A or B"
12
13config A
14	bool "A"
15
16config B
17	bool "B"
18
19endchoice
20
21config FOO
22	bool "FOO"
23	depends on A
24
25choice
26	prompt "Choose X"
27	depends on FOO
28
29config X
30	bool "X"
31
32endchoice