1.B (visible as a funnel cloud)
2.D (Tornadoes cause extensive damage to structures and disrupt transportation, power, water, gas, communications...,)
2.C
3.D (... but occur most often in the spring and summer months....)
4.A (Tornadoes can strike in any season, but occur most often in the spring and summer months. They can occur at all hours of the day and night, but are most likely to occur between 3 p.m. and 9 p.m.)