basis risk 不是因为标的物不同造成的吗 为啥1错了

NO.PZ2016082404000015问题如下 Whiof the following statements is/are true with respeto basis risk? I. Basis risk arises in cross-heing strategies, but there is no basis risk when the unrlying asset anhee asset are intical. II. A short hee position benefits from unexpectestrengthening of basis. III. A long hee position benefits from unexpectestrengthening of basis.   I anII   I anIII   II only   Ill only ANSWER: C Basis risk can arise if the maturities are fferent, so answer I. is incorrect. A short hee position is long the basis, whimeans thit benefits when the basis strengthens, because this means ththe futures priops relative to the spot price, whigenerates a profit. Strengthen of basis是指t时刻，现货价格大于期货价格，为什么这个情况是short futures会获益呢？可以具体下逻辑关系吗？

NO.PZ2016082404000015问题如下 Whiof the following statements is/are true with respeto basis risk? I. Basis risk arises in cross-heing strategies, but there is no basis risk when the unrlying asset anhee asset are intical. II. A short hee position benefits from unexpectestrengthening of basis. III. A long hee position benefits from unexpectestrengthening of basis.   I anII   I anIII   II only   Ill only ANSWER: C Basis risk can arise if the maturities are fferent, so answer I. is incorrect. A short hee position is long the basis, whimeans thit benefits when the basis strengthens, because this means ththe futures priops relative to the spot price, whigenerates a profit. 这里long hee是指long期货还是现货？清楚啊老师

NO.PZ2016082404000015 问题如下 Whiof the following statements is/are true with respeto basis risk? I. Basis risk arises in cross-heing strategies, but there is no basis risk when the unrlying asset anhee asset are intical. II. A short hee position benefits from unexpectestrengthening of basis. III. A long hee position benefits from unexpectestrengthening of basis.   I anII   I anIII   II only   Ill only ANSWER: C Basis risk can arise if the maturities are fferent, so answer I. is incorrect. A short hee position is long the basis, whimeans thit benefits when the basis strengthens, because this means ththe futures priops relative to the spot price, whigenerates a profit. 基差变大，有两种可能受益，一个是long现货，一个short futures，这里的short hee是特指short futures吗？

NO.PZ2016082404000015 问题如下 Whiof the following statements is/are true with respeto basis risk? I. Basis risk arises in cross-heing strategies, but there is no basis risk when the unrlying asset anhee asset are intical. II. A short hee position benefits from unexpectestrengthening of basis. III. A long hee position benefits from unexpectestrengthening of basis.   I anII   I anIII   II only   Ill only ANSWER: C Basis risk can arise if the maturities are fferent, so answer I. is incorrect. A short hee position is long the basis, whimeans thit benefits when the basis strengthens, because this means ththe futures priops relative to the spot price, whigenerates a profit. 老师您好，请问2，3要怎么理解。