A) Geography/Navigation (i) State the location of D. (ii) What is the difference in longitude between C and B? (iii) Calculate the length of the circle of latitude 60 deg S. (iv) Calculate the distanc

Point C is at $40^\circ$ W longitude.
Point B is at $40^\circ$ W longitude.

Since both points are at the same longitude, the difference is $0^\circ$.
The difference in longitude between C and B is $\boxed{\text{0}^\circ}$.

The radius of the Earth is $R = 3437 \text{ nm}$.
The latitude is $\phi = 60^\circ$.
The length of the circle of latitude $L$ is given by $L = 2 \pi R \cos \phi$.

Given $\pi = 3.14$ and $\cos 60^\circ = 0.5$.

The length of the circle of latitude $60^\circ$ S is $\boxed{\text{10799.98 nm}}$.

Point C: $60^\circ$ S, $40^\circ$ W
Point D: $60^\circ$ S, $50^\circ$ E
Common latitude $\phi = 60^\circ$ S.

Since one point is West and the other is East, add their longitudes.

The distance $d$ is given by $d = \Delta \lambda \times 60 \text{ nm/degree} \times \cos \phi$.

$\cos 60^\circ = 0.5$.