Indeed, good point! I should not assume all (d) are (a). I suspect it is true for the majority of cases nonetheless. In fact in one of the chat groups it was possible to vote for multiple options (because there are no proper polls on Signal) and several people voted for (a) and (d) - I counted these as (a) - but none voted for (c) and (d).
Apparently I didn’t vote, but my memory is I was torn between (c) because it was obvious and (d) because (c) was obvious.
Indeed, good point! I should not assume all (d) are (a). I suspect it is true for the majority of cases nonetheless. In fact in one of the chat groups it was possible to vote for multiple options (because there are no proper polls on Signal) and several people voted for (a) and (d) - I counted these as (a) - but none voted for (c) and (d).