The correct option is
D speak
In order to fill in the blank with the most suitable verb, we need to understand the usage of 'make'. 'Make' means to force someone to do something. If 'make' is used in a passive (voice) sentence, we use the word 'to' along with the verb. In an active sentence, we do not use 'to' with the verb. The verbs without the marker 'to', are called bare infinitives.As the given sentence is in the active voice, we will use the bare infinitive here.
NOTE: Here, 'made' is used as the main verb, which describes the sentence in past tense. Though the sentence is in the past tense, the bare infinitive will always be in its original form.
Option A - 'To speak' can't be used here, as the verb 'speak' is accompanied by the marker 'to', and hence we can conclude that it is not a bare infinitive. Hence, option A is incorrect.
Option B - 'To speaking' can't be used because we never use the participle form of the verb with the marker 'to'. Also, we need a bare infinitive here. Hence, option B is incorrect.
Option C - 'Speaks' is the third person form of the verb 'speak'. As we need the verb in its original form, we can't use 'speaks' here.
Option D - 'Speak' is a verb in its original form and is a bare infinitive to be accompanied by the main verb 'made' in the sentence. Hence, option D is the correct answer.
'My uncle made me speak to my old friends.'