What is the most likely decay for the fe-53 nucleus?

The element number of Fe is 26, which means that the number of neutrons of the following isotopes is:

53-Fe: 27

54-Fe: 28

56-Fe: 30

57-Fe: 31

58-Fe: 32

59-Fe: 33

Because 53-Fe has too few neutrons when compared to the other isotopes we can rule out any decay that involves losing a neutron: (alpha decay, beta decay) So, this isotope will prefer to decay by electron capture or positron emission (assuming the system has about 1 MeV to spare), but in each case the product will be the same: 53-Mn (long-lived radioisotope).