Seven pulleys are connected with the help of three light strings as shown in the figure below. Consider $P_3,P_4,P_5$  as light pulleys and pulleys  $P_6\text{\hspace{0.17em}\hspace{0.17em}and\hspace{0.17em}\hspace{0.17em}}{P}_7$ have masses m each. For this arrangement, mark the correct statement (s)

Tension in the string connecting  $P_1,P_3\text{\hspace{0.17em}\hspace{0.17em}and\hspace{0.17em}\hspace{0.17em}}{P}_4$ is mg/3 

Tensions in all the three strings are same and equal to zero

Acceleration of  $P_6$ is g downwards and that of $P_7$ is g upwards 

Tension in the string connecting $P_1,P_3\text{\hspace{0.17em}\hspace{0.17em}and\hspace{0.17em}\hspace{0.17em}}{P}_4$  is zero