The correct answer is: Only assumption I is implicit.
The statement only says that the party president has directed that no member of the party will give press briefing or interviews to governments and private T.V. channels about the discussion in scheduled meeting of the party. It does not say anything about whether the party members will observe this directive or not. So, assumption I is implicit.
However, the statement does not say anything about whether the general public will come to know about the happenings in the scheduled meeting of the party. It is possible that the party members will observe the directive and not give any press briefing or interviews, but still the general public will come to know about the happenings in the scheduled meeting through other means, such as leaks or rumors. So, assumption II is not implicit.