The outcome of tossing a coin is either a head or a tail.
Looking at the given table,
Event A = A tail in both the first and last tosses = THT, TTT
Event B = Two or more tails = TTH, TTT, HTT, THT
Event C = Alternating tail and head with either coming first = TTH, THH, HTT, HTH, THT. HHT
Recall,
probability = number of favorable outcome/number of total outcomes
Total number of outcomes = 8
Probability of event A = 2/8 = 1/4
Probability of event B = 4/8 = 1/2
Probability of event C = 6/8 = 3/4