Option C is the appropriate option to complete the given sentence because Option C expresses the use of simple future tense. Simple future tense is used to indicate an action which is going to start in the near future. Here, the programme is going to start in 'five minutes'.
Option A expresses the use of simple present tense, but simple present tense is used to indicate a habit, a universal truth or a fact, which is not the case in the given sentence. Therefore, Option A gets ruled out.
Option B expresses the use of present continuous tense, but present continuous tense is used to indicate an action which is continuing at the given point of time. In the given sentence, the action, ie. the programme, has not yet started.
Option D expresses the use of simple past tense, but simple past tense is used to express an action which happened / occurred in the past. In the given sentence, the action, ie. the programme, has not yet started.
Therefore, the complete sentence is: There's a programme on television that I want to watch. It will start in five minutes.