The open door policy’s main argument was that

It called for protection of equal privileges for all countries trading with China and for the support of Chinese territorial and administrative integrity.

although the crusades failed to capture jerusalem, they had several major impacts on western europe. they increased the authority of the king: sometimes nobles died in battle without leaving an heir in which case the king got their land. kings passed taxes to pay for the crusades.

b. they tried to evict the squatters from the area.

so sorry if wrong