It was hot in the room and the men began to (loose) ______their ties.
Scientists have done countless experiments to show that praise is far( effective )______ than criticism in improving human behavior.
甲国居民有来源于乙国所得100万元,甲、乙两国的所得税的税率分别为40%、 30%,但乙国对外国居民来自乙国的所得实行20%的优惠税率,现甲国采用抵免法消除国际重复征税并与乙国签订了税收饶让协定。请回答以下问题: 甲国对上述所得应征所得税税额为( )。
A. 40万元
B. 20万元
C. 10万元
D. 0