The start finger i (in steady alternation of i,m) accommodates the string crossing between A ③ and B ② for beats 1 & 2.  The start finger of m accommodates the string crossing between D ② and E ①  for beat 3.

This right-hand finger is the best of the two and includes a in the alternating pattern (m,i,m,a)   At the end of the 1st beat, a is the only option, since using i would be awkward to the string crossing ② and ①.

In the second version, alternating m, i on non-adjacent strings ③ & ① puts an uncomfortable spread between the fingers and may cause unecessary lower right-arm movement.  The first version—alternating a, i— is the most natural for the hand and keeps the right-arm position steady.

When simultaneously playing p on ⑥ and fingers on ①, it's helpful to use a, so that the reach between thumb and fingers is minimized.    Also in this context, a,m on ①  &  ② facilitates the switch to ②  &  ③ with m, i, making the right hand steadier.

Generally, when playing two consecutive notes on the same fret but on different strings, two different left-hand fingers are used.  In this example, the D ② with 4 is followed by 3 on C ⑤.   This ensures a more musical connection (legato).

The other choice here—3 on D ②, could have been followed by 2 on C ⑤.  Though this would be more labored, since 2 just played A ③.

The best option for fluid left-hand fingering is to circulate all four fingers and avoid repeating/overworking any one.

This example is similar to Ex. 5—4 on F ④ followed by 3 on G ⑥ is most fluid.  3 on F to 2 on G is another option, but overuses 2, since it just played E ④.  Notice also that beginning the passage with 4 on F ④ helps to reinforce playing it again on the & of beat 2.

The first option is optimal.  When placing 3 on A ③, leave it there for the following 3rd beat.  This passage could be right-hand fingered more than one way as shown.

The first version might tempt some to jump 3 from G ①  to D ② which is not legato playing.   This second version is better since 4 on G ①, leaves 3 available for D ②.   Notice that bass note B is fingered with 1, but some hands might feel more comfortable with 2.