What conditions are typically required for a tropical wave to develop into a tropical storm?
a) Sustained wind speeds of at least 35 mph, a well-defined circulation pattern, and warm sea surface temperatures
b) A central pressure below 1000 mb, wind speeds of 20 mph, and dry atmospheric conditions
c) Low humidity, a high-pressure system, and wind speeds above 50 mph
d) Cool sea surface temperatures, an increase in wind shear, and low atmospheric pressure