In an A.P., the sixth term $\mathbf { a } _ { 6 } = 2$. If the $\mathbf { a } _ { 1 } \mathbf { a } _ { 4 } \mathbf { a } _ { 5 }$ is the greatest, then the common difference of the A.P., is equal to\\
(1) $\frac { 3 } { 2 }$\\
(2) $\frac { 8 } { 5 }$\\
(3) $\frac { 2 } { 3 }$\\
(4) $\frac { 5 } { 8 }$