How many time divisions are covered by those same periods 72

How many time divisions are covered by those same periods?

7.2, 37, 7.4 or 39

What is the frequency of this picture in Hz?

Each division (by division, we mean by default, a major division.) in the above picture is worth 2ms. What is the period (in seconds) of this signal?

0.0023 s, 0.0046 s,0.0092 s, 9.2 s, 4.6 s or 2.3 s

1) 7.4 time divisions , f=67.56 Hz

2) 0.0092 s, f= 108.696 Hz