Incorrect
Natural factors can cause seasonal effects, but there is a better answer.
Incorrect
Administrative measures can cause seasonal effects, but there is a better answer.
Incorrect
Religious traditions can cause seasonal effects, but there is a better answer.
Correct
"All of the above" can cause seasonal effects. Warmer weather in the summer, end of the tax year,
and buying Christmas gifts can all be causes of seasonal effects, depending on the particular series.