Which of the following sentences is a clear example of a complex sentence in English grammar?

Introduction / Context:
This question tests your ability to recognise sentence types, especially complex sentences. In English grammar, understanding the difference between simple, compound, and complex sentences is essential for good writing and for answering transformation and error detection questions in exams. A complex sentence combines an independent clause with one or more dependent clauses.

Given Data / Assumptions:
- We must pick one sentence that is complex.
- A complex sentence contains one main (independent) clause and at least one subordinate (dependent) clause.
- The options include sentences with and without subordinating conjunctions like "when".

Concept / Approach:
A complex sentence is built when a subordinate clause is attached to a main clause using subordinating conjunctions such as when, because, although, if, and since. The subordinate clause cannot stand alone as a complete sentence. In contrast, a compound sentence connects two independent clauses with a coordinating conjunction like and or but. A simple sentence has only one independent clause.

Step-by-Step Solution:
Step 1: Examine option b: "My dad laughed when I told a joke." This contains main clause "My dad laughed" and subordinate clause "when I told a joke". The word "when" introduces the dependent clause.
Step 2: Check whether "when I told a joke" can stand alone as a full sentence. It cannot, so it is a dependent clause.
Step 3: Confirm that the presence of one independent and one dependent clause makes sentence b complex.
Step 4: Analyse the other options and notice that they either have only one clause or two independent clauses joined by "and", making them simple or compound rather than complex.

Verification / Alternative check:
Option a, "The cricket match was cancelled yesterday", has one subject and one predicate, which makes it a simple sentence. Options c, d, and e each contain two independent clauses joined by "and", for example "He sang" and "she danced". Two independent clauses joined by a coordinating conjunction form compound sentences, not complex ones. Only option b clearly shows the structure main clause plus dependent clause.

Why Other Options Are Wrong:
- The cricket match was cancelled yesterday: simple sentence with one clause, no subordination.
- He sang and she danced: two independent clauses joined by "and", so compound sentence.
- She cooked dinner and he washed the dishes: again two independent clauses, so compound sentence.
- The sun set and the stars appeared: also a compound sentence with two independent clauses joined by "and".

Common Pitfalls:
Many learners confuse compound and complex sentences because both have more than one verb. The key is to look for subordinating conjunctions and check whether one clause depends on the other for complete meaning. Whenever you see words like when, because, although, or if introducing a clause, there is a strong chance that the sentence is complex.

Final Answer:
The sentence "My dad laughed when I told a joke" is the complex sentence.