Quiz 1 — Named parameters

Consider a function:

sub f(:$a, :$b) {
    $a - $b
}

1

What are the valid ways to call it?

0	f(1, 2)	Positional arguments passed, not named.
1	f(a => 1, b => 2)
0	f(a = 1, b = 2)	Assignment operator instead of a pair constructor.
1	f(b => 2, a => 1)

For the same function, what do the following calls return?

−1	`f(a => 1, b => 2)` returns (: 1, −1 :)
−1	`f(b => 2, a => 1)` returns (: 1, −1 :)	The order of named arguments does not matter.
1	`f(a => 2, b => 1)` returns (: 1, −1 :)