Which of the followind expression is equivalent to (st)(6)?
As(t(6))
Bs(x) × t(6)
Cs(6) × t(6)
D6 × s(x) × t(x)
As(t(6))
Bs(x) × t(6)
Cs(6) × t(6)
D6 × s(x) × t(x)