When a coin is tossed, it will appear either a heads or a tails. The coin in the problem is tossed twice, the possible outcomes when we tossed a coin twice are as follows:
1. First toss and second toss results in both heads, represented as H, H.
2. First toss results in heads while the second toss results in tails, represented as H, T.
3. First toss is tails while the second toss results in heads, represented as T, H.
4. First and second toss results in both tails, represented as T, T.
Hence, the option that best represents the sample space for the tossing of a coin twice is the last option.