The answer is most likely 4 but I think you need a table or a marked hygrometer to work this out. You can't really work out humidity by the given temperatures. All you can know for sure is that there is a strong chance of rain because dew point is only 1 degree away. (I think what they want you to do is 29/30 x100)
To answer you question, The two main ingredients are Heat and coolness.
A net population decline resulting from an "excess of deaths over births".
Option: A
<u>Explanation</u>:
Demographic transition is a shift from higher to lower level of fertility and mortality.Rapid development in industrialization and urbanization in 
century resulted into enormous population growth. But decline in early 
century covered many reasons like consequences of two calamitous wars, where Europe suffered large population declination due to battle death and civilian causalities in World War I and II. Hence the acceleration of population growth in 19th century but downfall in 20th is also considered as balance.
