Which of the following infinite geometric series converge?
1+2+4+…1 + 2 + 4 + \dots1+2+4+…
1+0.5+0.25+…1 + 0.5 + 0.25 + \dots1+0.5+0.25+…
1−1+1−1+…1 - 1 + 1 - 1 + \dots1−1+1−1+…
1−0.5+0.25−…1 - 0.5 + 0.25 - \dots1−0.5+0.25−…