How many ship-design options did the Royal Navy consider?

How many ship-design options does the Royal Navy usually consider, and which is selected?

Roughly five options, with the second from the bottom often chosen, though both the number and the selection vary.

The rule of thumb is roughly five alternatives, with the second from the bottom usually chosen. Both the number of proposals and the selection vary. Some programmes have four or six options, including one example where the third of six was selected.