It takes a good telescope to see the moons of Neptune. I can’t see the moons of Neptune with my…

The correct choice is: “If you know the area of a circle, you can find its circumference. You cannot figure out the circumference. Therefore, you do not know the area”

The argument treats a good telescope as something that lets you see Neptune’s moons: if I have a good telescope (P), I can see the moons (Q). It then observes that I cannot see the moons (not Q) and concludes that I do not have a good telescope (not P). The form is: If P then Q; not Q; therefore not P.

The circle argument has exactly this form: if you know the area (P), you can find the circumference (Q); you cannot find the circumference (not Q); therefore you do not know the area (not P).

“If you have a surfboard, you can surf …” and “You can write a letter … with a pencil …” both argue If P then Q; not P; therefore not Q (they deny the condition instead of the result), which is a different and invalid pattern. “It takes two to tango …” moves from doing the tango to having a partner, which infers the requirement from the activity, again a different structure.