21. Which of the following enables an ammeter to make a correct measurement of current in a circuit element

(there may be more than one correct answer):

(a) connect the ammeter in series with the element and just before it;

(b) connect the ammeter in series with the element and just after it;

(c) connect the ammeter in parallel with the element;

(d) connect the ammeter between the high potential side of the element and ground; and/or

(e) none of these is the correct way to use an ammeter.