Clarification for underlying type of an integer constant expression

[dg1980]

Dear MISRA team,

is the underlying type of

Code:

static_cast(1U)

a) uint8_t (underlying type of an integer literal in chapter 6)?

or

b) uint16_t because the static_cast is taken into account (see static_cast(expression) in chapter 6)?

If the answer is a) then it would be impossible to make this line of code compliant with rule 5-0-10, right?

[code]const uint16_t MASK = 1U