Step 1: Classify the noun "equipment".
"Equipment" is an uncountable noun, like "furniture" or "information". Uncountable nouns cannot be counted directly with numbers and do not take an "s" to form a plural.
Step 2: Recall how to count an uncountable noun.
To express a number of an uncountable noun, English uses a counting unit before it, such as "a piece of", "two pieces of", "an item of". The noun itself stays in its base singular form after this unit.
Step 3: Apply this pattern to the blank.
Since we need to say there are two separate items, the correct pattern is "two pieces of equipment", where "pieces" carries the plural and "equipment" stays unchanged.
Step 4: Eliminate the wrong choices.
"Two equipments pieces" wrongly pluralizes "equipment" and reverses the word order. "Two pieces of equipments" wrongly pluralizes "equipment" even after "pieces of" already shows the count. "Two equipments" pluralizes an uncountable noun directly, which is not standard.
Final Answer:
The only grammatically correct phrase is "two pieces of equipment", so option (b) is correct.