The correct answer is: Only argument II is strong.
Argument I is not strong because it is based on the assumption that reservation of seats and posts on communal basis will check most of the inter-communal biases. However, there is no evidence to support this assumption. In fact, some studies have shown that reservation can actually lead to increased inter-communal tensions.
Argument II is strong because it is based on the principle of secularism. Secularism is the principle of separation of religion and state. In a secular state, the government should not favor any particular religion or religious group. Reservation of seats and posts on communal basis would violate this principle.
Therefore, only argument II is strong.