The Church$-$Turing Thesis states that any effectively computable function can be computed by a Turing machine. Which of the following best captures the essence of this thesis?

$($a$)$ All programming languages have the same computational power.

$($b$)$ Any algorithm can be implemented on a Turing machine.

$($c$)$ Modern computers are much more powerful than Turing machines.

$($d$)$ The Church$-$Turing Thesis is no longer relevant in modern computer science.