I am trying to ask a questions like these:
Which security should I buy: a foreign-listed bond issue with a five-letter ticker ending with "Q", or a domestically-listed convertible preferred share issue with a five-letter ticker ending with "A"?
Is my use of the colon correct? Should I have used an em-dash instead? For example: "Which security should I buy — a foreign-listed ...".
Which one do people usually buy — the first one, or the second?
Is my use of the em-dash correct, or should I have used an em-dash instead?