In the English Grammar Profile, there are two points in the category of Modality at B2 which are practically the same and include the same examples.
Point 147 is:
‘must’ the question form.
Point 161 is:
‘must’ to ask about obligation and necessity.
Notice that most must question examples in the TED corpus are much more complex than yes/no questions:
I began to wonder, why must it be so binary?
Can you wash tomorrow, or must it be today?
What sort of talents must we be sure to defend?
How many times must a man look up before he can see the sky?
How long must women wait for liberty?
How much more suffering must we take?
And what must that feel like? (speculation, certainty, deduction is probably C1)
We consider the ability to use an adverb in the middle position at least C1 ability:
What must we gracefully exit out of to be fit for these futures?
An iWeb cluster search for must * * * * ?does not give us the usual subject modal verb inversion:
1 MUST BE GOOD, RIGHT? 84
2 MUST BE TRUE, RIGHT? 76
3 MUST BE BETTER, RIGHT ? 45
4 MUST BE A BETTER WAY? 26
5 MUST BE DOING SOMETHING WRONG? 20
must _p _vvi
1 MUST I USE 186
2 MUST I TAKE 173
3 MUST I PAY 166
4 MUST I GO 154
5 MUST I WAIT 143
6 MUST WE WAIT 131
7 MUST YOU USE 107
8 MUST I SAY 100
9 MUST YOU GO 99
10 MUST WE GO 96
11 MUST YOU TAKE 87
12 MUST WE TAKE 78
13 MUST I PROVIDE 75
BBC News
Dallas Business Journal14 MUST WE SAY 75
15 MUST I COMPLETE 73
16 MUST WE BELIEVE 72
17 MUST I SUBMIT 66
18 MUST I MAKE 65
19 MUST YOU MAKE 65
20 MUST WE FORGET 63
21 MUST WE THINK 61
22 MUST I KEEP 56
23 MUST WE MAKE 56
24 MUST I GET 52
25 MUST THEY THINK 52
26 MUST I GIVE 51
27 MUST I TELL 51
28 MUST I REGISTER 50
29 MUST WE USE 50
30 MUST YOU PAY 50
31 MUST YOU KEEP 49
32 MUST I BUY 48
33 MUST I PUT 48
34 MUST I FILE 47
35 MUST I MEET 46
36 MUST IT FEEL 46
37 MUST WE GIVE 45
38 MUST I THINK 43
39 MUST I BRING 42
40 MUST I CHANGE 42
41 MUST I REMIND 42
42 MUST YOU KNOW 42
43 MUST I DIE 41
44 MUST I LEAVE 40
45 MUST I LIVE 40
46 MUST WE KEEP 39
47 MUST WE CONTINUE 38