An experiment succeeds twice as often as it fails. The probability that in the next six trials, there will be at least 4 successes, is:

​​​$$\left( \frac{2}{3} \right)^4 \cdot \frac{31}{9} \\$$​​

​​​$$\left( \frac{2}{3} \right)^4 \cdot \frac{28}{9} \\$$​​

​​​$$\left( \frac{2}{3} \right)^5 \cdot \frac{29}{9} \\$$​​

​​​$$\frac{16}{81} \cdot \frac{13}{9} \\$$​​