An analyst does research about debt covenants. Which of the following least likely lowers the risk to creditors A debt covenant specifying a minimum level of the borrower's:

A. current ratio.
B. dividend payout ratio.
C. interest coverage ratio.

在骨骼肌收缩过程中，能与细肌丝结合的是()

A．Na＋

B．K＋

C．Ca2＋

D．Mg2＋